How to Improve

I just recently went from being a begineer to reaching an intermediate. I currently am playing good with 1400s and 1500s in USCF but now I want to know what is the next step to improve. I think I am around 1430s or 1450s right now. Can someone recommend what I can do next and also chess books that can help me improve? Thanks. I haven't really been a reader but now I want to give it a try.

You just posted that you were entering your first real tournament a couple of weeks ago.  How did that go?  

There are no books designed for 1440 rated players.  You can look at your own games, the ones you lost, and figure out where you lost them. In the opening?  Blow an ending? That will give you a clue as to what to study next.

There are plenty of books for you to improve with.  Grabbing Israel Gelfer's Positional Chess Handbook is great.  At your level (as well as my level around 2000+) its still all about tactics.  So doing tactical puzzles can't hurt.

I should have won the tournament with 4.5/5 points but I was up against a 1956 and i blundered a drawn game and I was underestimating my other opponent and played too aggresssive that he saw a combination to win my queen.