Check the flight manual for the official procedure (I don't have one to hand at the moment). I set full power then raise the flaps to 20 if they were at 30 degrees. Do not raise the flaps any more than this until safely away from the ground (I use 200+ ft QFE, above 65kts, with a positive rate of climb as the minimum).
Avoid confusing the techniques for the missed approach and touch-n-go. In one of my first circuit lessons in a 152 I got confused and tried to fully raise the flaps before applying full power when performing a go-around at about 50 ft. Lucky to have a very competent instructor that day!
MC