i always fly the downwind at reduced throttle (if i cruise at 3/4 then i will use 1/2) and on base i will progressively reduce throttle and on final depending on alt, will cut throttleto high idle. If the plane is too fast or too high, the best way to slow down or bleed off alt/speed is to enter a forward slip (ailerons in opposite direction of rudder) If the plane stalls easily, keep a bit of power on and pitch the nose down to maintain speed. hold the slip till u are about ready to flair, then as you flair, slowly stop the slip. If you release controll inputs too fast or too high, the plane will pickup speed and lift, and baloon. it takes alot of practise to get it down pat, but after a couple flights of touch and go's you will start to get a good feel for it.
Just remember, like everyone else has been saying: dont play with trim (it will get you in trouble) throttle controlls alt pitch contolls speed. Like i was told when i got my PPL: its all 3d thinking. Picture what will happen with every controll input and be ready to react.