In the opening and in the middlegame, the loss of a rook for a minor piece and one pawn is usually less serious than the loss of a pawn. Cecil Purdy, On The Endgame
Do not use analysis engines blindly, but only as an additional tool to check your analysis. Andreas Tzermiadianos, How To Beat The French Defence: The Essential Guide To The Tarrasch
In complicated positions with things able to be taken or exchanged, it is almost certain that the best move is to grab something. Don't dither. It's your opponent's move next time, so don't give him free rein, force him. Cecil Purdy, CJS Purdy's Fine Art Of Chess Annotation And Other Thoughts - Volume Three
There are two basic approaches for White to obtain the advantage in the opening. He can open 1.e4 and aim for rapid development, or he can play d4 and c4 in the first few moves (the "Queen's Gambit") and play for space. Larry Kaufman, The Chess Advantage In Black And White
A knight often has problems fighting against pawns in an ending, with particular difficulties when trying to stop a rook's pawn. John Littlewood, Chess Coaching
Classic games are very instructive in the sense that plans attempted by the masters of the past were often carried out without serious opposition, so we get to see how the idea is executed in practice. Nikolay Yakovlev, Chess Blueprints