Amateur tennis serves rarely improve because most players hit baskets of balls hoping for magic. The serve is a chain of motions, fixed in order. Train them in order and the serve actually changes.
Week 1: Toss only, no swing
Stand at the baseline, toss balls and let them land in front of you. Goal: every toss lands inside a coin-sized spot just inside the baseline, slightly ahead of your front foot. Two hundred tosses across the week. Boring, decisive. Inconsistent toss = inconsistent serve forever.
Week 2: Trophy position pause
Add the swing setup, but freeze at "trophy position" (racket up behind your head, off-arm pointed at the toss). Hold for two full seconds before continuing. This is where most amateurs rush. The pause forces you to actually load the legs and shoulders.
Week 3: Pronation only
Half-court serves, no power, focus only on snapping the wrist down and out at contact (pronation). The ball should curve sharply. Speed comes from this snap, not from your arm swinging hard. Hit fifty serves per session, three sessions.
Week 4: Stitch it together
Full motion at 70% pace. Twenty serves to deuce box, twenty to ad box. Track first-serve % only. If you're under 60%, slow down further. Speed comes back automatically once the chain is grooved.
Don't skip a week
Skipping ahead to "full motion" undoes the chain. Trust the order.
Find a tennis court and book a single-hour slot for each session. The plan needs four weeks, no more.