A few comments on the opening and early middle game:
Move 17) It is normally better to approach from the other side (C6). There is more territory to be made on that side, and less danger from nearby W strength. W already has a low position with the stone at O3, so there is no need to worry about W making a large territory on the bottom.
Moves 14 and 21) The W attachments in both cases seem to help B more than W, since B gets good extensions in both cases. W loses opportunities to invade (around Q9) or pincer (around J4).
Move 27) Excellent. W approached much too closely. This pincer should give a good result, helping B secure territory on the left as W runs.
Move 35) Here B is trying for too much. Simply extend to D13 and take fourth line territory, while maintaining the attack. Don't push W toward the weak B stones to the right, and don't give W any weaknesses to play against.
Move 37) But now to be consistent B must extend to E12. It is better to resign than to play anything else
If W gets too good a result from an attack on the weak B stones to the right, lose the game fighting. Letting W capture the E13 stone is hopeless.Move 45) The corner position after W cuts is interesting. It is worth spending some time to read out, as the territory swing in the corner could easily be 20 points. Can B atari at C17, then butt at E17? That would threaten to capture the corner with B18 or to connect underneath at F18. If this does not work, then sacrifice the D17 stone cleanly by playing B18 instead of D18. The way B actually played gave W additional profit.
Move 55) As Ed pointed out, the standard follow-up to the previous move would be to block at P16. This is a good sequence to learn. Try reading out some continuations to convince yourself that W cannot profitably push through on either side.
Move 59) is bad shape, pushing from behind, inviting a perfect W hane, leaving the B stones short on liberties. Jumping to L15 would be better locally. B is strong enough here to fight if W cuts, and B can easily give up the two stones at N16, as they are not accomplishing much, pressed directly against a strong W group.