Towards the beginning of the game, I like to try to control the center of the board. I use pawns and knights to make sure I control the middle four squares. Meanwhile, I'm looking for moves that will let me get a material gain on the opponent. Be aggressive in making them react to you. If I'm not forcing him/her react to my moves, I'm losing. And if he/she should be reacting, and doesn't, then I look to see if I missed something, and if not, then I gain the advantage.

Sometimes, I go with another tactic, or blend it with controlling the center - attacking the king's bishop's square. Learn the Scholar's Mate, which involves attacking that square with the queen and bishop, and work that into your game. You can pile on pieces to making that work, and it'll frustrate some opponents into making mistakes.

Tactics training helps a lot. I like echess[1], it has a good selection of tactical puzzles. Try to solve one a day and you should see significant improvement in your game within a month.

For a game against an advanced player you must master the openings which can be hard (I always make mistakes in the opening stages).

[1]http://en.lichess.org/training/17424

I visualize what advertising people call a "heat map". That is I look at the board as a whole then imagine where all the pieces can move to.

Write down at least some of your games then have them critiqued later, or critique them yourself - but not immediately after a game; I once dropped in on a chess club that has heavily into post-game critiques and found it so unpleasant that I never attended again.

Yes, I developed got a secret trap maneuver that works from any board position, it's an insta-win or at least a stalemate every single time. Unfortunately my memory of it was hypnotically suppressed in order to keep myself safe from the Mechanics' Institute -- I'd need two of three friends of mine to say certain codewords to unlock it.

1. Learn opening principles. 2. Practice tactics. 3. Play more. 4. Go to step 2.

https://www.youtube.com/user/thechesswebsite and chess.com