Made too many positional mistakes

In this game, I didn't make any glaring blunders (at least any I could identify), just a series of inaccuracies that allowed my opponent to improve his position until my position became hopeless. I want to know if I pinpointed the times when I made inaccuracies, and what I should have played instead of what I played. This was an OTB game, 60 minutes with a 5 second delay. When I resigned I had a little under 10 minutes left and my opponent had a little more than 10 minutes left. Time pressure wasn't a factor. I have not done the computer analysis of this game.

I didn't know my opponent's rating until after the game, which is just as well because I would have known I had no chance playing someone rated that much higher than me. I have lost every tournament game I have ever played against anyone rated above 1800.

After the game, I asked my opponent if he wanted to analyze it, and he said, "No, I want to rest. That game wore me out." I replied, only half-jokingly, "I'm a lot older than you and I lost, I'm the one who should feel worn out."