I think Uberdude is correct. You do not seem to imagine your opponent's stones as objects of attack. As you noted in the game file 77 should have attacked the right side stones. But also...
In the game you responded to White's invasion with 'a'. You can't do that!

Try 1, or 'b', or 'c', or even 'd'.
$$Bc Whatever you do, don't play 'a'!
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X X . . . . . . . . X . . . . . |
$$ | . . . O O X X O . O . d b . . X . . . |
$$ | . X O . . O O . . . . c 1 W . . X . . |
$$ | . X X O O . . . . . . . . . a . . . . |
$$ | . O O X . . . . . . . . X . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . X . . X . . . |
$$ | . . . X . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . O . . X O . . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . O O . . . . . . . . . . . . O . . . |
$$ | . X X O . . . . . . . . X O O . X . . |
$$ | . . X O . . . . . X . . X X . X . . . |
$$ | . . X O . . . . . , . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Bc Whatever you do, don't play 'a'!
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X X . . . . . . . . X . . . . . |
$$ | . . . O O X X O . O . d b . . X . . . |
$$ | . X O . . O O . . . . c 1 W . . X . . |
$$ | . X X O O . . . . . . . . . a . . . . |
$$ | . O O X . . . . . . . . X . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . X . . X . . . |
$$ | . . . X . . . . . , . . . . O X X . . |
$$ | . . . . . . O . . . . . O . . X O . . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . O O . . . . . . . . . . . . O . . . |
$$ | . X X O . . . . . . . . X O O . X . . |
$$ | . . X O . . . . . X . . X X . X . . . |
$$ | . . X O . . . . . , . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
In the game you played 'a' below. This would only make sense if it were some type of long-range attack on the White right-side stones. It wasn't. So do something else instead. What would White have done if you cut at 1?

The two cuts at 'b' and 'c' mean that White is not going to get out of this situation without significant damage.
$$Bc What does White do here?
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X X O . . . . O O X . . . . |
$$ | . . X X X . . O . . . . O X . . . . . |
$$ | . . . O O X X O . O O O X X . X . . . |
$$ | . X O . . O O . . . . X X O . . X . . |
$$ | . X X O O . . . . . . . . . X . . . . |
$$ | . O O X . . . . . . . . X . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . X . . X . . X . . . |
$$ | . . . X . . . . a , . . . . O X X . . |
$$ | . . . . . . O . . . . . O . . X O . . |
$$ | . . b 2 4 . . . . . . . . . O . O . . |
$$ | . O O 1 3 5 . . X X O . O . . O . . . |
$$ | . X X O . . . . O X . . X O O . X . . |
$$ | . . X O . . . . O X . . X X . X . . . |
$$ | . . X O c . . . . O . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Bc What does White do here?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X X O . . . . O O X . . . . |
$$ | . . X X X . . O . . . . O X . . . . . |
$$ | . . . O O X X O . O O O X X . X . . . |
$$ | . X O . . O O . . . . X X O . . X . . |
$$ | . X X O O . . . . . . . . . X . . . . |
$$ | . O O X . . . . . . . . X . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . X . . X . . X . . . |
$$ | . . . X . . . . a , . . . . O X X . . |
$$ | . . . . . . O . . . . . O . . X O . . |
$$ | . . b 2 4 . . . . . . . . . O . O . . |
$$ | . O O 1 3 5 . . X X O . O . . O . . . |
$$ | . X X O . . . . O X . . X O O . X . . |
$$ | . . X O . . . . O X . . X X . X . . . |
$$ | . . X O c . . . . O . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
In the game White played 1 and 3 as a standard tesuji to make an eye along the side. But that only works if 3 is sente. However, here the very strong Black position at the bottom is the signal that 3 can't be sente. Capture 1!

That means no eye for White and more points for Black.
$$Wc Think about the alternatives
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$$ | . . . . . . . . . . . . . O O O X . . |
$$ | . . . . . X X O . . . . O O X X X . . |
$$ | . . X X X . . O . . . . O X . . . . . |
$$ | . . . O O X X O . O O O X X . X . . . |
$$ | . X O . . O O . . . . X X O . . X . . |
$$ | . X X O O . . . . . . . . . X . . . . |
$$ | . O O X . . . . . . . . X . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . X . . X . . X . . X . 2 . |
$$ | . . . X . O X . X , . . . . O X X 1 . |
$$ | . . . . . . O . . . . . O . . X O 4 . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . O O . . . O X X X O . O . . O . 3 . |
$$ | . X X O . . O . O X . . X O O . X 5 . |
$$ | . . X O . . . . O X . . X X . X . 6 . |
$$ | . . X O . . . . . O . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wc Think about the alternatives
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$$ | . . . . . . . . . . . . . O O O X . . |
$$ | . . . . . X X O . . . . O O X X X . . |
$$ | . . X X X . . O . . . . O X . . . . . |
$$ | . . . O O X X O . O O O X X . X . . . |
$$ | . X O . . O O . . . . X X O . . X . . |
$$ | . X X O O . . . . . . . . . X . . . . |
$$ | . O O X . . . . . . . . X . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . X . . X . . X . . X . 2 . |
$$ | . . . X . O X . X , . . . . O X X 1 . |
$$ | . . . . . . O . . . . . O . . X O 4 . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . O O . . . O X X X O . O . . O . 3 . |
$$ | . X X O . . O . O X . . X O O . X 5 . |
$$ | . . X O . . . . O X . . X X . X . 6 . |
$$ | . . X O . . . . . O . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
In the game White cut with the marked stone and you surrendered with 2. Don't do that unless you have read out the alternative. The cut is unreasonable. Just kill it with 1 and 3.

White tries extending the liberties of the cut stones? Calmly connect with 5, forcing 6, and 7, forcing 8.
$$Bc What does White do here 2?
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$$ | . . . . . . . . . . . . . O O O X . . |
$$ | . . . . . X X O . . . . O O X X X . . |
$$ | . . X X X . . O . . . . O X . . . . . |
$$ | . . . O O X X O . O O O X X . X . . . |
$$ | . X O . . O O 8 . . . X X O . . X . . |
$$ | . X X O O . . 7 X . . . . . X . . . . |
$$ | . O O X 5 3 1 . . . . . X . . . . . . |
$$ | . . 6 O . X W 2 4 . . . . . . . . . . |
$$ | . . X O O O X . . X . . X . . X . X . |
$$ | . . . X . O X . X , . . . . O X X O . |
$$ | . . . . X X O X . . . . O . . X O . . |
$$ | . . . O . O O . . . . . . . O . O . O |
$$ | . O O X . . O X X X O . O . . O . O . |
$$ | . X X O . . O . O X . . X O O . X X . |
$$ | . . X O . . . . O X . . X X . X . . . |
$$ | . . X O . . . . . O . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Bc What does White do here 2?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . O O O X . . |
$$ | . . . . . X X O . . . . O O X X X . . |
$$ | . . X X X . . O . . . . O X . . . . . |
$$ | . . . O O X X O . O O O X X . X . . . |
$$ | . X O . . O O 8 . . . X X O . . X . . |
$$ | . X X O O . . 7 X . . . . . X . . . . |
$$ | . O O X 5 3 1 . . . . . X . . . . . . |
$$ | . . 6 O . X W 2 4 . . . . . . . . . . |
$$ | . . X O O O X . . X . . X . . X . X . |
$$ | . . . X . O X . X , . . . . O X X O . |
$$ | . . . . X X O X . . . . O . . X O . . |
$$ | . . . O . O O . . . . . . . O . O . O |
$$ | . O O X . . O X X X O . O . . O . O . |
$$ | . X X O . . O . O X . . X O O . X X . |
$$ | . . X O . . . . O X . . X X . X . . . |
$$ | . . X O . . . . . O . . O X . , X . . |
$$ | . . X X O . . . . O . . O . O X . X . |
$$ | O O X O O . . . . . . . . . . O X . . |
$$ | . X X O . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]