Player serves from one side. Coach feeds random ball as a return. Player reacts and hits the next shot to the open space.
It is important that coach feeds different balls to make process more effective. Balls should be short, deep, flat, with topspin/backspin, to backhand/forehand etc. Coach should emphasise proper decisions related to different balls to improve also tactical skills.
Indoor courts give players less time and less room. Help them sharpen their split step, shorten their swing and stay calm, and winter becomes a season of real progress.
A tiebreak is a short sprint where every point is worth the same as a break of serve. The players who win them are rarely the ones who hit hardest. Here is how to coach the patterns, habits and scoreboard thinking that win the big points.
Most club players practise the serve on its own and then have no idea what to do with the ball that comes back. Serve plus one is the pattern that turns a good serve into a won point.