There are 3 main levels at TST (but then obviously there are levels within the levels and the levels blend together sometimes based on what players are capable of).

• 2v2 Level
• 3v3 Level
• Game intelligence level

Having said this - the most important part of coaching is the ability to develop a relationship with the players you coach. 

From the moment they get there, be pleased to see them, ask them about their team/games etc, be very positive and supportive through out the session, and be engaged the whole time, and especially in the games at the end. At the end don't disengage - be involved. For most players the best coach is the one who is the most inspiring - this is rarely the one who knows the most.

I know at the end it is tempting to start packing up, but i would much prefer you to stay engaged in the games. I can stay all night packing up if need be - but you cant be replaced during the games.

In terms of parents whinging - it is usually about the lack of engagement during the games (coaches chatting to each other, sitting down and just watching etc).

If you join in the games, help the players who need it the most. Coaches who play, have a 'lose 2 touch' / 'first time finish' rule. No physicality allowed. Get a balance between winning and losing games.