If you want to get better at the middle game, you have to stop playing moves like 17 (

below) in the opening. You have to be able to imagine White's response at

and ask yourself, "What next?" After

(19 in the game), White should have immediately captured at

. White makes a huge profit in what was originally Black's corner. In addition, it is now inevitable that

will turn out to be over-concentrated since "a" and "b" are miai. There are various alternatives for Black in this corner but learning joseki is not the theme of this analysis. The point here is that 17 in the game damages Black's position. Black does know enough to realize that connecting against the atari would be slack (17 becomes a wasted move) but probably there was nothing better.
$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . 4 . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 b . |
$$ | . . . . . . . . . . . . . a X X 5 . . |
$$ | . . . , . . . . . , . . . . O O X 3 . |
$$ | . . . O . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . 4 . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 b . |
$$ | . . . . . . . . . . . . . a X X 5 . . |
$$ | . . . , . . . . . , . . . . O O X 3 . |
$$ | . . . O . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Later on in the play against the invaders in the upper right, Black can consider driving White in the direction of the lower right. Imagine that Black plays the hane at

below and prevents White from pushing through at the top. Black 7 and 9 channel White along the side and Black is going to be able to justify some additional moves that make use of the lower right stones in attacking White.
$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . O . O . . . . . . X . X O O . . |
$$ | . . O , . . . . . , . 5 . . X X X O . |
$$ | . . O X . . . . . . . . . 4 . . . X . |
$$ | . . X . . . . . . . . . 3 2 . O X . . |
$$ | . . . X . . . . . . . . 1 O . . . . . |
$$ | . . . . . . . . . . . . . X . O . . . |
$$ | . . . . . . . . . . . . . . 6 . . . . |
$$ | . . . , . . . . . , . . 7 . 8 X . . . |
$$ | . . X . . . . . . . . . . . . 9 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X . . . . . . . . . . . X X . . . |
$$ | . . . , . . . . . O . . . . O O X O . |
$$ | . . . O . . O . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . O . O . . . . . . X . X O O . . |
$$ | . . O , . . . . . , . 5 . . X X X O . |
$$ | . . O X . . . . . . . . . 4 . . . X . |
$$ | . . X . . . . . . . . . 3 2 . O X . . |
$$ | . . . X . . . . . . . . 1 O . . . . . |
$$ | . . . . . . . . . . . . . X . O . . . |
$$ | . . . . . . . . . . . . . . 6 . . . . |
$$ | . . . , . . . . . , . . 7 . 8 X . . . |
$$ | . . X . . . . . . . . . . . . 9 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X . . . . . . . . . . . X X . . . |
$$ | . . . , . . . . . O . . . . O O X O . |
$$ | . . . O . . O . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
One more point. On the left side, look at what happens when you answer

with

below. The stone at 2 means that if you capture at 7 (as you did in the game), you have an inefficient shape. You have used five stone to capture 1 when you only need 4. If you are going to capture at 7, you want to do so instead of playing 2. In this case, the ko (if White plays 2) may be hard to fight. Black has a lot at risk along the left side. So playing 2 makes some sense. Then however, we cannot capture at 7. We have to play 4 instead. Imagine that White can successfully connect at 5 (which wouldn't happen in the game). Even then, Black would be better off to cut. It takes some reading but not a lot. The White stones cannot escape. Black becomes strong so White becomes weak. This is the essence of fighting in the middle game.
$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . O . O . . . X . X X . X O O . . |
$$ | . . O , . . . . . X O O X . X X X O . |
$$ | . . O X . . . . . O . . O O . . . X . |
$$ | . 5 X . . . . . . . . . . . . O X . . |
$$ | . . . X . . . . . . . . . O . . . . . |
$$ | . 3 1 4 . . . . . . . . . X O O O . . |
$$ | . 2 X O 6 . . . . . . . . X X . X O . |
$$ | . X O 7 . . . . . , . . . . . X . X . |
$$ | . . X . 8 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . X . . |
$$ | . O X . X . . . . . . . . . X X . . . |
$$ | . O X , X . . . . O . . . . O O X O . |
$$ | . . X O O . O . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . O . O . . . X . X X . X O O . . |
$$ | . . O , . . . . . X O O X . X X X O . |
$$ | . . O X . . . . . O . . O O . . . X . |
$$ | . 5 X . . . . . . . . . . . . O X . . |
$$ | . . . X . . . . . . . . . O . . . . . |
$$ | . 3 1 4 . . . . . . . . . X O O O . . |
$$ | . 2 X O 6 . . . . . . . . X X . X O . |
$$ | . X O 7 . . . . . , . . . . . X . X . |
$$ | . . X . 8 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . X . . |
$$ | . O X . X . . . . . . . . . X X . . . |
$$ | . O X , X . . . . O . . . . O O X O . |
$$ | . . X O O . O . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Okay, ONE MORE "one more point". If White answers

below (instead of 117),

kills.
$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . O . O O . . . . . . O . |
$$ | . . . O . O . . . X X X X . X O O . . |
$$ | . . O , . . . . . X O O X . X X X O . |
$$ | . . O X . X . . X O . X O O O 1 . X . |
$$ | . O X . . . . . . X X O . . X O X . . |
$$ | . . . X . . . . . . 4 O . O . 2 . . . |
$$ | . O O O . . . . . 5 . 3 . X O O O . . |
$$ | . X X O . . . . . . . X . X X . X O . |
$$ | . X . X O . . . . , . . . . . X . X . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . X . O O . . X . . O . . O . . . . . |
$$ | . O O . X . . . . . . . . . . X . . . |
$$ | . X O X . X . . . . X O X X . . X . . |
$$ | . O X . X . . X X . X O O O X X O . . |
$$ | . O X , X . . . O O . . . . O O . O . |
$$ | . . X O O . O . . . . . . . . . O . . |
$$ | . . . X X O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . O . O O . . . . . . O . |
$$ | . . . O . O . . . X X X X . X O O . . |
$$ | . . O , . . . . . X O O X . X X X O . |
$$ | . . O X . X . . X O . X O O O 1 . X . |
$$ | . O X . . . . . . X X O . . X O X . . |
$$ | . . . X . . . . . . 4 O . O . 2 . . . |
$$ | . O O O . . . . . 5 . 3 . X O O O . . |
$$ | . X X O . . . . . . . X . X X . X O . |
$$ | . X . X O . . . . , . . . . . X . X . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . X . O O . . X . . O . . O . . . . . |
$$ | . O O . X . . . . . . . . . . X . . . |
$$ | . X O X . X . . . . X O X X . . X . . |
$$ | . O X . X . . X X . X O O O X X O . . |
$$ | . O X , X . . . O O . . . . O O . O . |
$$ | . . X O O . O . . . . . . . . . O . . |
$$ | . . . X X O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]