Plans are usually based around pawn structures: Static features of the position. Which open files can you occupy with your rooks, can your knights be placed on advanced squares. I don't know anything more than very basic strategy yet, but it normally depends on which opening you play.
It's not very easy to put on simple terms but this may help as a general summary: http://en.wikipedia.org/wiki/Pawn_structure
This is a good website for tactics and mating motifs. http://www.chesstactics.org/
I first played chess when I was 8 (I'm 25 now). Only played once in a while at that time. Then I played again on a semi-regular basis in high school, as a diversion from paying attention in study hall.
More recently, I started playing online with a friend, and found that I absolutely love the game. I looked through a few games and was usually able to see why certain moves were made, but seldom able to see the best move before it was made.
I've started doing puzzles, and I've improved a bit, but aside from opening/development and trying to get checkmate when the board has cleared out a bit, I still find myself making somewhat arbitrary moves, never really having a larger goal in mind.
I have no idea how to actively work towards a situation where the opportunity to checkmate becomes more likely, aside from "take away pieces and make it hard for the opponent to move around," which seems kind of basic and vague.
Can someone give me advice on how to plan on a big larger scale/longer term than just pins and forks and such?
I feel like I understand (to a degree) how to use the "weapons," so to speak, but not where to aim them.
Hopefully I'm making sense and don't sound like an idiot.