The safest target for beginners is deep and toward the side glass. A serve that lands close to the side wall forces the returner to choose between hitting early or letting the ball reach the glass.
Trying to hit the line is risky and rarely worth it early on. A slightly slower serve that lands consistently in the same area will win more points than an aggressive serve that misses one out of three times.
A good beginner serve usually has three characteristics:- enough height over the net to avoid clipping it
- depth that pushes the returner back
- placement that makes the return uncomfortable, not fast