There's a lot of resources on how to count the score, but usually it's framed for the middle game or end game. Which makes sense; that's when you need to know the score. But counting an unfinished game is difficult, especially if it's close. Is that half point ko that threatens to kill your group necessary to win? Better hope you can count each and every last stone on the board, plus any prisoners, and then account for komi.
So here's some counting practice. To channel Kageyama, anyone who can't count even a finished game has a doubtful future

Nothing clever going on in these positions, except for the occasional dead group (but it should be obvious what is dead). First who does your gut tell you won? Then try to count to find who actually won, and by how many points. Not all of them are close, but the exact (edit: relative) score matters, so no handwavy W+xteen.
For prisoners,

means 7 black stones are white's prisoners.
Correct count is in the hide tags (but I may have transcribed wrong, so take them with a grain of salt if you keep counting something different).
Position 1Black got everything he wanted, and white failed to make sabaki. Should white just resign gracefully?
- Click Here To Show Diagram Code
[go]$$Bc Komi: 0.5, prisoners

$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . . O . . . . . . . . . O O O X X . |
$$ | . . . , . O O O O O O O O X O X . . . |
$$ | . . O O O X X O X O X O X X X X X . . |
$$ | O O O X X . . X X X X X . . . O . . . |
$$ | O X X X . X X . X . . . . . . . O . . |
$$ | X . . . . . . . . X . . . . . . . . . |
$$ | . X . . X X X X X O X O . . . . . . . |
$$ | . . X X X O O X O O X X . . O , X . . |
$$ | X X O X O O . O . O O X . . . X . . . |
$$ | X O O O X . . . . O X X X . . . . . . |
$$ | O O . . . . . . . O O X X . . . . . . |
$$ | . . . . . . . . . O X X . . . . . X . |
$$ | . . . O . . . . . O . X X . . . O . . |
$$ | . . . , . . . . . O O X O . . , X O . |
$$ | . . O . O . . . . . O O X X X . X . . |
$$ | . . . . . . . . . . . . O O X . . . . |
$$ | . . . . . . . . . . . O O X X . . . . |
$$ +---------------------------------------+[/go]
Position 2Such a messy board! How can I do a proper count if you can't even keep things tidy.
- Click Here To Show Diagram Code
[go]$$Bc Komi: 6.5, prisoners:
, 
$$ +---------------------------------------+
$$ | . . . . . . . . . . O O X . . . . . . |
$$ | . . O O O O O . O O O X X . . . . . . |
$$ | . O . . . O . O O X X . . . . X X X . |
$$ | O O O O O X O . O O X . X X X O O X X |
$$ | X O X X O X O O . O . X O O O . . O X |
$$ | X X X X X X X X O O . X O O . O O . O |
$$ | . X O X O O O X X O X X X O . . . . . |
$$ | . X O O O . O X X O X X O X . . . . . |
$$ | . X O . O O X O X X . X O . . . . . . |
$$ | . X O X O O X . . X . X O . O , . . . |
$$ | X X X O X X X . . . X O O X O O O O O |
$$ | X O X O X O . X . X O . . O X O X X O |
$$ | O O O O O X X . X X O O O O X X X X X |
$$ | . . X O O X O X O X O O X O X . . . . |
$$ | . . X . . O O X O O O O X X O O X . . |
$$ | . . O O O O . X X O X . X X X , X . . |
$$ | . O O O X O X . X O X X X O . X . . . |
$$ | O O X O X X . X X O O X O X X . . . . |
$$ | . X X X X . . . X . O O O O O X . . . |
$$ +---------------------------------------+[/go]
Position 3White's corner is huge! Does black have enough to counter that?
- Click Here To Show Diagram Code
[go]$$Bc Komi: 0.5, prisoners:
, 
$$ +---------------------------------------+
$$ | . X X X O . . . O X X X X O . . O O O |
$$ | . . X O . O . . O O O X O O O O O X O |
$$ | . X X O . O . . . O X X X O . X X X X |
$$ | . O X O O . O O O O O X . O X X . . . |
$$ | . X O O . . O . . . O X O O O O X . . |
$$ | . X X O O O X O O O X X X O . O X . X |
$$ | X . . X X X X X O X X X O O O . X X O |
$$ | O X X X O X X . X . . X X O X X X O O |
$$ | O O O O O . O X . . . . O X X X O O . |
$$ | O O X X O O O X . , . X X . . X O . . |
$$ | O X X . X O X X . . . . O X X O O O . |
$$ | X . X X X O X O X . . . . . . X X O . |
$$ | . . . O X O . O X . . . . . . X X O . |
$$ | . . X . X O . O X . . . . X X X O . . |
$$ | . . . . . X X O X . X X X O O . O . . |
$$ | . X . X X X O . O X X O O . . O . . . |
$$ | X . X O X O O O O O O . . O . . . . . |
$$ | X X O O O O . . . . . . . . . . . . . |
$$ | X O O O . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
Position 4Dame and dumplings everywhere
- Click Here To Show Diagram Code
[go]$$Bc Komi: 0.5 prisoners:

$$ +---------------------------------------+
$$ | . . . . . O X X . . . X O O . O . . . |
$$ | . . . . O . O X . X X . X O O . . . . |
$$ | . O . O . . O O X . . X X O X O O O O |
$$ | . . O X O . . . O X . X O O X X X X O |
$$ | O O X X O . . . O . X O O X . . . . X |
$$ | O X X . O O O O . X X O X . X . X X X |
$$ | X X O O O X X O . O X X X X . X O X O |
$$ | . X O X O X X X O O X X O X X O O O O |
$$ | . X X X O O . X X O O X O X O O . O O |
$$ | . . X O O X X . X X O . O O O O X O O |
$$ | . . X O O O X X O X O O O O O X X X O |
$$ | . X O O . X X O O X O X X X X X X X O |
$$ | . . X O O . X X O X O O O X O X X X X |
$$ | . X X X X X X O O X X X O X O O O O X |
$$ | X . . . X O O O X X O . X X X O . O O |
$$ | O X X X O O X O X X . . . . . X O . . |
$$ | O O O O . O X X . . X . . X . X O . . |
$$ | . . . . . O O X . X . . . . X O O . . |
$$ | . . . . . . O O X . . . . X O O . . . |
$$ +---------------------------------------+[/go]
Position 5Lots of dead stones here, but don't let them distract you.
- Click Here To Show Diagram Code
[go]$$Bc Komi: 6.5 prisoners:

$$ +---------------------------------------+
$$ | . . . . O O X . . . . . . . . . . . . |
$$ | . . . . O X . X . . . . . . . . . . . |
$$ | . O O O O X . . . . . . . O . X . X . |
$$ | . O X O X X . . . , X . . X X X X . X |
$$ | . X X X O X . . . . X X . X . X X X O |
$$ | . . X O O O X . . X O O X . X O O O O |
$$ | . . X O X X X X O X X O O X X O O . . |
$$ | . . X O X O O X X X O O . O O O . O O |
$$ | . O O O X O X O X . X O . . . . O X O |
$$ | . X X O . O . O X O X O . O . O O X X |
$$ | . X O . O . O O O X X X O . O X X X . |
$$ | . O O . . O . O X . . X O O O O X . . |
$$ | . . . . O X X X . . . O X O X O O X . |
$$ | . . . . O X . . X . O X X X X O X X . |
$$ | . O . O O O X X . . X O X O X X X X . |
$$ | . O X X X . O O X X . O X O O O X O . |
$$ | . X X . O . . O X X X O X . . X O O . |
$$ | . . . O X O O . O X X O X . . X X . . |
$$ | . . . . . . . . O O X . O . . . . . . |
$$ +---------------------------------------+[/go]