Pick a chess puzzle theme and solve free rated puzzles of that kind, as many as you like. Themes name the idea you need to find: tactics such as forks, pins, skewers and discovered attacks, checkmate patterns, endgames, and the phase of the game. Each theme page explains the idea and takes you to puzzles that use it.
Tactical themes include fork, pin, skewer, discovered attack, double check, deflection, sacrifice and trapped piece. Checkmate themes include mate in 1, mate in 2, mate in 3, back rank mate and smothered mate. You can also practise endgames, such as rook, bishop, knight, queen and pawn endings, and positions from the opening and the middlegame.
chessGM