Try going through the study plans, they've helped me improve over 100 points in the last month alone. Also, play lots of live games with standard time controls (at least 15|10).
Becoming a 1500 chess player -> Help?

Play over your games. Find where you are weak and work on that first. Study some books especially openings. Join the USCF and play tournament games!

I'll suggest the most popular advice: study tactics, more tactics and more more tactics. Read tactics books like Winning Chess Tactics by Seirawan and solve online tactics exercises like the Tactics Trainer.

Play against those stronger than yourself. When you do a seek. Have it, let's say, set for only 50 points lower than your current rating and 200 above.
This has helped my game the most imo.

Have you tried chess 960? Maybe its crazy, but I never played it until recently. I've played 6 games, and won 6 games. I'm about 1540, so I came to the conclusion, that I think better outside of the box, than inside the box.
Hey guys, I have been playing chess for 2 years or so and have been noticing some improvements at the game. However, I seem to be stuck at the 1100 rating and I would really like to know how to improve from that point up to a 1500 rated player.
Thank you very much! All help will be greatly appreciated =)