From moves 1 through 15, both sides played reasonably well. There might be alternatives that would be worth a few more points, but it was good play for kyus.
Let's look at the board after move 15:
$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . c c . . . . . . O . X . . . |
$$ | . . . O . . . . . O . . . . . X . . . |
$$ | . . . . . . . . . . . . . a . . . . . |
$$ | . . X . . . . . . . . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . f . . |
$$ | . . d . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . e . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X . . . . . , . . . . . O . . . |
$$ | . . O . . O . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . c c . . . . . . O . X . . . |
$$ | . . . O . . . . . O . . . . . X . . . |
$$ | . . . . . . . . . . . . . a . . . . . |
$$ | . . X . . . . . . . . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . f . . |
$$ | . . d . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . e . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X . . . . . , . . . . . O . . . |
$$ | . . O . . O . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
In the upper right, black is solid. There is not much for white to do. You could play 'a' with the threat of 'b', but black just replies with something around 'b' himself, taking a big corner.
In the lower left, both sides are solid. A move like B3 is an endgame move for you. It doesn't really threaten black.
In the upper left, a play around 'c' is a decent play for both. It is gote for white, but rather big. It is risky for black, because when white gets stronger in the corner, white playing at 'd' can be a problem for black.
In the lower right, there is more room than any other place on the board. The largest gap on the entire board is along the bottom edge, and the second largest gap is on the lower right side. A stone here by either player is big. And if he can play it in sente, that is even better.
As white at move 16, I would have played at 'e'. It gets a loose grip on corner territory, prepares to pincer any black stone that tries to live on the lower side, and prepares a pincer/invasion around 'f'.