How to improve when you are sub 2000?

I really want to know how to improve my game but I don't have a solid idea of how to. From what I've heard I should be doing tactical and positional puzzles but I don't really know what they are and where to find these puzzles as well as how do they help me improve. I would also like to know how long does it take to see improvement? Is chess improvement for the average player a long-term goal? This sort of question has probably been asked a lot of times but I would still appreciate all constructive answers. Also please try to give direct answers so I know how to improve. Thanks.

A puzzle is a position with a specific solution.  The solver is only given the position and whose turn it is to move and is asked to find the solution.  Often a solution is a series of moves, not just 1 move, and will contain the best (or theoretically best) moves.

In a positional puzzle, the general idea is also important to understand, not just the moves.  Sometimes there is a hint to help find a solution, sometimes a puzzle's difficulty is given so the solver knows what to expect.

Tactical:
Chess.com tactics trainer.
Chesstempo.com
Software like CT-ART
Books (google chess tactic book for example).

Positional:
Less commonly done in puzzle form, but there are a few books out there.  When people talk about solving puzzles they almost always only mean tactical puzzles.

Tactical puzzles in particular improve a few core skills.  First of all they help you learn common tactical patterns like removing the defender or forking.  Another benefit is they force you to calculate and visualize.  Another is that while solving you must practice some good analysis habits such as:  trying to invalidate your candidate move,  looking for undefended pieces, and focusing on forcing moves.

Positional puzzles teach common positional ideas and depending on the difficulty can also involve a lot of calculation, although sometimes it may only ask for the main idea.

Everyone is different.  Some factors include how much and how hard you work, your age, the number of strong players in your area, and yes even talent.  It's important to play games too, not just do puzzles.  The games should be long enough that you have time to incorporate new knowledge (i.e. not blitz or bullet).  Chess strength can be said to come in two parts, knowledge and performance.  Just because you know something doesn't mean you're good at using it in your games yet.

Hundreds of points of improvement are most usually measured in years.  Plateaus are common though, where in spite of study and work the results of games aren't improving.  Then, suddenly, you may gain 100 rating points in a few months.

Yes, chess improvement is always a long term goal.

Improvement also involves playing players stronger than you (not so much stronger that you never win), analyzing your own games for mistakes (without help e.g. from a computer), reading books, playing in OTB tournaments, and coaching.

Thanks for the advice, other answers also greatly appreciated

tactic training, and more tactics, combined with a proper dose of opening, endgame, and positional practice in the right training program should give you rating boosts of upwards of 500 rating points per year (up to 2000 at least...)

What was your rating 12 months ago?

I did some research and it says 2087!

I should clarify that the rating boosts are up to 2000. The higher the rating you get, the harder it is to gain rating... That said, you should still be consistently moving up!

Sorry, USCF site was down, now I see it :)

It's rare to gain 500 points in 1 year if you're playing a lot.  If you're underrated, or rated 1000, then sure (if you work hard).  But 1500 to 2000 in 1 year I think very few people are able to do that!

1300->1800 in one year, then 1800-> 2000 is very possible

I will agree that is possible.  The conditions you give are pretty important.  Good training and lots of work.