variety is the key. Narrow, normal, wide, fingers out, fingers in, one hand up, one hand down. Superman position, claps, dive bombers, handstand, claps, one handed, hands on a medicine ball, half pushups (floor then half way up, back down), elbows to the floor and back up, roll off to a side (elbow down, shoulder down, back up, etc. All sorts of variations, doing only one type will isolate specific muscles and strengthen only on that angle, change things up.