As a general rule, it is not good policy to exchange in the early stages of a game the long-reaching bishop against the knight, whose power does not extend beyond a certain circle. Emanuel Lasker, Common Sense In Chess
Before thinking of any particular move, examine all your possible moves that smite. And before making a move, examine all your opponent's possible smites in reply. Cecil Purdy, CJS Purdy's Fine Art Of Chess Annotation And Other Thoughts - Volume Two
Knights are usually the more valuable minor pieces in the opening. But the bishops have the future because they inevitably grow in range as pawns are traded. Andrew Soltis, The Wisest Things Ever Said About Chess
In a position where you have to look for a plan, think first about what kind of pawn-play you should be aiming for. If no pawn-play is in prospect, ask yourself what to undertake with your pieces. Vladimir Popov, Chess Lessons
In opposite-coloured bishop endings keep your pawns on 'your' colour if you want to draw; if you are playing for a win you should keep your pawns on the opposite colour from your own bishop. Lars Bo Hansen, How Chess Games Are Won And Lost