This diagrammed position occurred after 19...Na5. White could have played 20.Bxd5! with a clear advantage. My plan of 16...a6, 18...b5, and 19...Na5 was faulty. I should have played 16...h4 with the idea of 17...Qe5 and 18...Qd6.
The second diagram shows the position after 23...Nf5, a mistake allowing 24.Nxd5! which my opponent overlooked. A better move for me would have been 23...Nc6.