How do I develop as a player?

I have been playing chess for as long as I can remember, but have never really had any scholastic training. For the last couple of years, my rating has been pretty static around 1400. The games I win is mostly by exploiting my opponents' mistakes, and rarely based on anything more than tactics. When I play stronger players, I usually find myself overwhelmed without really understanding why. I guess my knowledge of opening theory and position play is quite weak, which stronger players exploit quite easily.

What would you recommend that I do to become a stronger player?

You need a good book on the positinal aspect of chess. If you reached that level with just tactics then you are a talented player. With any book on positional chess you could easily improve a few hundred points in a hurry!

Get a copy of Pawn Power in Chess by Hans Kmoch. His book will give you the strategic framework you need going forward. The pawn structure dictates where the pieces belong and what the plans should be. If you don't understand this type of stuff you're like a pool player who can make the easy shots but has no idea where the cue ball is going.

What helped me a lot was just to look up all the openings in Wikipedia. You're allowed to use opening databases and articles in correspondence chess, so just start a game and google the first moves (e.g. "1. d4 d5 2. c4 Nf6" will lead you to the Marshall Defense that you played against in your last game). It will give you some guidelines to consider your next moves and the reasoning behind them. If you play enough games, you'll soon have a good fundamental understanding of opening theory, which should give you a few hundred more rating points.

If you want to go beyond that, you need to specialize in specific openings and read through entire books. But that can wait - I've never read a chess book in my life and my rating here is now (a slightly inflated) 2100. Not that reading the books will cause you any harm; it's just that the way I described gives you a wider (albeit more shallow) view that may be just what you need in your stage of development. Once you've picked a few pet openings for both white and black and have enough practice with them, you might want to consider reading books that delve deeper into their theory.

Thanks for quick response and good tips. I will keep you updated on my progress.

One of the nicest metaphors I've read to describe the way I play :)

you can message me sir, so i can give you personal tips.