Your opening wasn't bad, taking solid enclosures and 2 space extensions. Perhaps you were slightly defensive, responding on the second line when you didn't need to at times, but they weren't too bad.
Here are some of the main mistakes.
playing on the first line so early is bad as there is very little impact on the rest of the game and S16 is a weakness that can still be exploited. Better at S16 or S15.
similarly. better at P11
empty triangle is bad shape. Eyespace is important because B's group is nearly surrounded. S12 is best to so that S11 becomes one eye and S13 is another eye.
important move since B's corner doesn't have many liberties and corners are important - if they are surrounded they don't have much space to live, but if they get out, they are very alive and hence have maximal influence nearby.
fancy (unusual)! but the direction is great since there is so much open space here and both players might make a moyo here. K5 is probably more normal or something like N4 if you want to push for efficiency.
slack, playing in an area already well controlled by W, not close enough to attack B, while B is taking key points all around.
separating to cut two weak groups and preventing D7. Looks good, though my preference would be to take territory with E3
good shape knowledge but perhaps slightly overconcentrated and unnecessary
unnecessary
unreasonable when B has been spending many moves to surround the G7 group. W should be happy to live cleanly with D2 instead.
safe and good locally but slack since B spent so many moves on the attack. W manages to live with both weak groups here deep inside B's main area which is a game-winning success.
excellent to push W low
W had a shape weakness and B normally pushes at E2 to keep up the threat of attacking. Perhaps not a big deal here since the H2 peep remains.
better to connect B4. Like this W can still push in from A3 (around 4 points difference). This move plays in your own territory.
- :w102: both sides are playing very small (around 3pt) moves when there are still 10pt moves on the board.
:b103: excellent, very big. The game has basically entered endgame already with all groups alive.
I'll stop here. I don't think W gained much after this point as both played solidly in the endgame, though there was a point where W at B15 was a major threat. B spent too many moves making just a few points in the centre but gained a lot by managing to get both B10 and B13 without W capturing them when W could have easily.