Here is a game I played against someone.
I reached the middle-game safely, and then I got a small advantage (despite him being rated 200 points above me), but I ended up walking into a sharp position which I should have avoided, and got mated.
White missed lots of chances of better moves to win this game. Black played 3...Qf6?! getting the Queen out too early. White should play 4.Nc3 and 5.Nd5 or just castle with 4.O-O.
After 4...a6, White should play 5.Bg5, attacking the Queen. Black then would probably play 5...Qd6. Now Black can play 6.Bxc6 bxc6 (6...Qxc6 allows 7.Nxe5) 7.O-O.
After 6...Nd4, White should play 7.Nbd2 and not allow Black to double up White's pawns. White could also play 7.Bxd4 exd4 8.c3 with a good game. White played 7.c3, allowing 7...Nxf3 8.Qxf3 Qxf3 9.gxf3 and doubled pawns. Not fatal, but weak.
Instead of 16.Nb6?! in the game, better is 16.Nxe5, winning the pawn and controlling the center with 17.d4 as the next move. It is most important to win material (or avoid the loss of material) at this level.
18.Ra8 might by OK if you want a draw, but 18.Rg1 or 18.Nc4 or 18.b4.
24.Bc1 may not be the best. I would have played 24.Rg2 so as not to worry about ...Rb1 and still protect the f-pawn.
26.d4?! is not as good as 26.Nxf7, winning another pawn.
After 28...Bg5, perhaps best is 29.Kc2!, breaking the pin and potential discovered check and threatening 30.Bxf4 or 30.Bxg5 if the knight moves.
Instead of 31.Rg2?? which allows Black to mate, best may be 31.hxg5!, and if 31...Nxf2+, then 32.Ke1 and White should come out ahead in the exchange if 32...Nxg4 33.fxg4 Rg2 34.Ne5. The moves may be 32.Ke1 Nd3+ 33.Kf1 h5 34.g6+ fxg6 35.Nf8+.
thank you very much! I'll try and take heed.