There is an easy way to make a workout hard: alternate between static and ballistic movements, loading the muscles with bodyweight and then asking them to explode and move through their full range of motion when they are already tired. If that sounds a tad hard it is because, it is. It is also highly effective delivering a high-burn body-shaping workout you really feel working five minutes in.
Extra Credit: Pick up the speed of your punches immediately after push ups.
