The chief considerations when playing chess middlegames should be to play for a strong and if possible winning position in the endgame. The pawn structure is formed and the minor pieces, Knights and Bishops, are developed.
These do battle for control of the center while the major pieces, Rooks and Queen, wait on the edge of the action. They will join the battle during the middlegame when the position calls for their power and influence.
There are several forms of advantage that chess players struggle for. Let's consider the relationship between
material and position. A material advantage, all other things being equal, should mean a favorable position. But remember, never put material gain ahead of positional concerns.