Tony, you owe it to yourself and the other guy to serve as hard as you can for your second serves, and first serves.
First of all, you need the practice. Two sets cannot tire you out from serving. If it does, your motion is flawed.
You need to hit your best serves so you can improve. Hitting pattycake is not improving at all.
If your opponent is getting your hard serves back at your level, then your "hard": serve is a pattycake anyways, and you need to improve it.
You have a choice of flat serves to THREE spots, top/slice serves to THREE spots, kick serves to TWO spots, slice serves to TWO spots.
Can you hit them all? If you can, you can beat RogerFederer most times.