Here's a practical advice:
Play correspondence chess, don't play live. When playing live, even 15|10, you don't have enough time to think. That's like 20-30 seconds per move, it's nothing.
You should play correspondence chess, think about every move several minutes, and only make a move when you're absolutely sure it's the best one you've got. It definitely helped me improve.
Good luck.
Eliran, how long have you been doing that? I've only played blitz and bullet, maybe 100 games in total longer than that, and I've gained 1300 rating pts in 5 years. It should not matter too much what type of chess you play, as long as you are learning and expanding your mind, and I really believe in taking breaks for 30 days or more to let all your information sink deeper into your mind.
A strong players doesn't necesarrily know alot of chess. He just knows how to find good moves. In a serious game, it doesn't matter whether Cabablanca or Morphy was born first, or who won which of their world championsships (actually they never played each other).
Correspondence chess is too slow.You do not need that much time 
so - if he makes like you suggest - then he get your rating then? ask him if that is good enough for him : )
I like to avoid the temptation to undermine a fellow chessplayer based on rating - especially Chess.com rating, remembering that many of us don't really take that at all seriously.
Stop being bad and start being AWESOME ! Go to a mirror and say it: I am awesome !
https://www.youtube.com/watch?v=BLyHWIXTrlI 
I got to 1400 in less a than 2 years. :D you are WRONG
JustADude80 wrote:
First off, play more and study less. Second think, accept the fact that you will lose a lot of games and don't worry about it. Third thing, set reasonable expectations. It takes years to be a 1400 or 1500 level player. You simply won't get there in a year or two. Fourth thing, do lots and lots of Tactics Trainer puzzles on this site. Every game has tactics. Fifth thing, pick one opening to play with white and stick to it till you learn it. Pick one black opening to play against e4 and one to play against d4. Stick to them till you learn them. Sixth thing, analyze your loses and understand why you lost.When you see what kind of mistakes you are making ask your self why. You might need to play 30 minute or even one hour games rather than 15 minute games. But you probably need to relax and just play.
Play for fun. Play because you like it. If you stop liking it, stop playing. Chess is a game. It is a complicated game that takes years to be good at. It is NOT a measure of how smart you are or how much time you work at it. It is just a game.
Your skill level depends on who you compare yourself to. "Not good" is in the eye of the beholder. Anderssen, Europe's champion, was "not that good" compared to Paul Morphy, and almost everyone on this site pales next to Carlsen. Don't be too hard on yourself about stuff like that.
As for improvement, I would suggest tactics problems, computer game analysis, and practice, practice, practice - especially with people who are better than you. If you can see what they do when they play, then you can replicate it and use it to your advantage.
Even if you try and just can't improve, just play the game for fun. It's not worth it to stress over chess ability, even if it is something that is important to you. It's better in the long run to just enjoy the game, and improve as you go if you can.
Hope this helps!
A-J-S