Piece development
Developing the pieces as quickly as possible is decisive for seizing the initiative and being first to launch an attack. If one side manages to get far ahead of the other in development (in mobilizing forces), a serious advantage in force can appear at once in some sector of the fight, and this advantage can be decisive.
Carrying out any task in chess goes hand in hand with hindering the opponent's efforts to carry out theirs. So while aiming for a favorable pawn structure, a player should try to worsen the opponent's; while developing pieces, a player should try to hinder the mobilization of the opponent's forces.
Following the principles of opening strategy, a player should not waste time — and so, except when creating or meeting tactical threats, should avoid moving the same piece several times, pushing the rook pawns, and so on.
