In case I haven’t mentioned it yet: Jeremy Silman’s The Amateur’s Mind is a gem. Two easy chunks inspired by one of his practice games with an amateur:
1) Decide where your “area of influence” is (usually the area on the board where you’ve got more space) and develop your pieces so that they strengthen your hold on that area. Don’t scatter the power of your pieces all over the board. Instead, focus on your area of influence and have your pieces act in concert. This will make it easier for you to develop a consistent, logical plan. In the position below, White’s area of influence is the queenside. Therefore, says Silman, developing the white-square bishop to e2 is more logical and more consistent than fianchettoing the bishop.
2) Fianchettoed bishops (like bishops in general) prefer an open centre. Fianchettoing the bishop to g2 is not only questionable because of White’s queenside space, but also because Black’s pawn on d5 disrupts the bishop’s diagonal and is safely guarded by his peer on e6. Of course, if Black’s centre pawn was weaker, then pressuring it with the fianchettoed bishop would be a more viable plan.