The position never simplifies since captured pieces are constantly being recycled. Draws are unheard of. King safety is paramount, so don't leave weak squares next to your king. This applies in particular to KB2.
Diagonal weaknesses are prey to dropped pieces.
Contact checks and knight checks are best because your opponent cannot drop a piece to interpose. This makes the knight a very powerful piece, often worth more than a rook. Pawns are quite useful for dropping in, to attack and to defend. It is illegal, however, to drop pawns directly on the first or the last rank. Always keep some pieces held in reserve, rather than dropping them in for no reason.