^^^
What should 1400 USCF rated player study?

Tactics. Endgames. Tactics. Pawn structures. Tactics. Model mating patterns (lolli, greco, anderssen's, anastasia's, morphy, paulsen, philidor, corridor, smothered, epaulette, etc).
... and Tactics.

Well, then I would like to personally suggest some tactics study, because that may help your game immensely.
Coming from a 1538 player, lol
Sure tactics. Besides the obvious, my leap from 1400 to over 1500 was largely a result from better evaluation technique and improving my ability to make better, more concrete plans. How did I improve that? I started to go over more annotated games by past greats and tried to find moves and plans in their games and then check if I was right or not.

Sure tactics. Besides the obvious, my leap from 1400 to over 1500 was largely a result from better evaluation technique and improving my ability to make better, more concrete plans. How did I improve that? I started to go over more annotated games by past greats and tried to find moves and plans in their games and then check if I was right or not.
Oh wow thanks for the good piece of studying. I appreciate it.

I've found that one of the biggest differences between a 1400 player and a 2100 player is not so much their ability to calculate... but WHICH moves the two players choose to examine.
Consider the following position. Which of White's possible moves would you choose to analyze?
...
...
...
I played Be2. It wins a piece or forces two connected passed Pawns in all variations.

My video lesson001 on YouTube and lasts 37 minutes. It has over 10,000 views. It explains how to maximize your study time to get the most in return. My group has over 7,700 members in just over 2 years, so I must be doing something right. You may auto join my group here and get access to all my YouTube videos.... http://www.chess.com/groups/join?id=14246

At my rating level I am very unsure of what to study.
Any help would be very appreciated
Economics.

If you haven't checked out Dan Heisman's "novice nook" at Chess Cafe that might be of interest to you.

My video lesson001 on YouTube and lasts 37 minutes. It has over 10,000 views. It explains how to maximize your study time to get the most in return. My group has over 7,700 members in just over 2 years, so I must be doing something right. You may auto join my group here and get access to all my YouTube videos.... http://www.chess.com/groups/join?id=14246
Thanks I appreciate it.

I've found that one of the biggest differences between a 1400 player and a 2100 player is not so much their ability to calculate... but WHICH moves the two players choose to examine.
Consider the following position. Which of White's possible moves would you choose to analyze?
...
...
...
I played Be2. It wins a piece or forces two connected passed Pawns in all variations.
Any advice on how to change this?
At my rating level I am very unsure of what to study.
Any help would be very appreciated