From your comments so far, I am not sure if you understand that the reason for action theoretically never comes from the players mind, but only from the board. There are only 3 situation where you have a small choice between 2 or 3 moves:
a) (seldomly) When the difference between 2 points is marginally small and you prefer one style over another. I.e. some players like to play more for territory, while others like large scale frameworks more. That makes a lot of sense, because you can not learn everything about that game. Focussing on learning one part of the game and sacrificing to not know so much about the other part improves the experienced level of play more then knowing little bit about everything.
b) (more often) When the whole Go community, even after thousands of years of research, in a situation still doesn't know the correct answer. For example we still don't know which opening is the best. There is a best for black and a best for white. You can be sure about it. But until now the game is so complex that we can't say it for sure. We are happy about this uncertainty, though. Because it is very likely that the game is boring in the moment we solved all of these questions. If that point is reached there is no creativity left in the game. Only the player with the bigger knowledge and counting ability will be better.
c) (most often seen) When you don't understand the situation correctly and didn't recognise all the influencing factors. In that situation you will lose points through your wrong conclusion, though. That happens to the beginner in nearly every move and to the expert also still quite often.
Just in case, that is not clear to you yet, I want to give an example.
- Click Here To Show Diagram Code
[go]$$c No matter what the players think, this group is alive or dies on a.
$$ --------
$$ | . a . X O . .
$$ | X X X X O . .
$$ | O O O O O . .
$$ | . . . , . . .[/go]
Another example:
- Click Here To Show Diagram Code
[go]$$c corners > sides > center
$$ -------------------------------------
$$ | . . a . . X . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . |
$$ | X X X X X X . . . . . . . . . . . |
$$ | . . . . . . . . . , . . . , X X X |
$$ | . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . X . . |
$$ | . . . . X X X X . . . . . . X . b |
$$ | . . . . X . . X . . . . . . X . . |
$$ | . . . . X . . X . . . . . . X . . |
$$ | . . . , X . c X . . . . . , X X X |
$$ | . . . . X . . X . . . . . . . . . |
$$ | . . . . X . . X . . . . . . . . . |
$$ | . . . . X X X X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . |[/go]
It is fact, that corners make most easily points, then sides and then the center. You see here 3 groups who make 10 points. (a) needs 8 stones for these 10 points, (b) needs 11 and (c) needs 18 stones. So it is clear that the 10 points in the corner are most effiently, while the 10 points in the center need a lot more work. And trying to build points also depends on life. A living group can focus on points, while without life it has to make life first. This fact will be used by your opponent to make a center group smaller, while it is impossible for your opponent to threaten the life of a corner group like this one:
- Click Here To Show Diagram Code
[go]$$c Can not be killed and has already around 12 points.
$$ --------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . X . . .
$$ | . . . , . . .
$$ | . . X . . . .
$$ | . . . . . . .[/go]
Okay, I hope now that this is clear, I'd like to repeat: Not the player decides what he wants to do. The board decides. The only thing a player can do, is understand the board and act accordingly. The moment you don't follow the dictatorship of the board you will play inefficient stones or create weaknesses in your position that your opponent can use, given he understands that there is a weakness and he knows how to exploit that weakness.
'nuf said. Let's talk about your thoughts about better moves in your game.
- Click Here To Show Diagram Code
[go]$$c You consider a or b, while preferring a.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . . . . . . . . . . . . . a b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . W . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I fully agree with you here. I added c as another option, because I also think that b is too close here, but a low move can also be considered. Which one you play is open to you. That is not, because there is not a best one, but because it makes no difference on your (and probably also on my) skill level. We can think about it, when we are on Dan level. Actually all 3 moves are good enough here. The all follow the situation of the board. Also they attack the lonely white stone. While this stone runs or fights for some life, we will be able to make some points. Also see here, that you don't make points directly at your strength in the top right corner. The battle is quite far away from it. But because your stones in the battle and your stones in the upper right corner can work together, the chances for white to establish a living group in the middle between them is quite low. A smart white player will probably not even try that. He will worry more about that this thing might grow bigger and bigger, and so he will try to limit it's growth. But killing it or putting something in its middle is too risky for white.
Now let's examine the result of the actual game situation a little more clearly.
- Click Here To Show Diagram Code
[go]$$c A situation not easy to understand.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , W . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . W . . . |
$$ | . . . . . . . . . . . . . . X X W . . |
$$ | . . . , . . . . . , . . . . . , W . . |
$$ | . . . O . . a a a a . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Do you remember what we said for an attempt from white on the right side, in the upper situation, where you choose to attack whites stone from the other side? We said, that white has a very hard time to go into the middle of both black groups on the right side again, because both should end up strong after the battle.
When we look here, white established a living group already (the marked white stones). His goal of destroying our strength is already accomplished, before we even started to form our strength. Our strength on the top side, can now not grow so much anymore. You can not see that yet, but with some more experience you will feel the pain here. The top right corner is like a flower on a very nutrient ground and with a lot of sunshine. Although you can not see it bloom yet, you already want to cry, knowing how beautiful it will be. But now white has put a cow directly next to the flower. How can it grow now? No sunshine anymore, every try to growth might be eaten away. How pittyful...
So what we actually did here, was to exchange our strong, beautiful plant in the top against a smaller one on the bottom side. Playing on one of the a's it also might grow, but never as big as the top. Also, failing to play an (a) will allow white to play there, growing its bottom left while killing our potential growth at the same time. Allowing your opponent to help himself while cutting down your potential is a very big mistake!
Last but not least, you say you don't know many josekis. I think that is totally okay. If you learn to read the board correctly you will play much better moves all the time, not just in the corners. Just know here, that this is not joseki. It is bad for black even when you don't consider the other corners!
The next position:
- Click Here To Show Diagram Code
[go]$$c Again a, b are your considerations.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . , . . . . . , . . . |
$$ | . . c . . . . . . . . . . . . . O . . |
$$ | . . . . b . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . X . X . X . . . . . . X X O . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . O . O . O . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Your b move is way too high. Now that you know, that the center is not so interesting as long as there are open sides and corners, I hope you know yourself that this move is not even worth thinking about. But (a) already is quite good. If you can recognise a situation like this and play there you will already have a lot easier life on the go board (well actually a harder one, cause you will very fast increase to higher ranks of opponents). A little better might be (c), though. This is a little lower and can form a base. A group that has a base, is alive and thus can consentrate on attacking opponents groups or growing to make some points.
That was a big post.

If you have any more questions, please ask.
