If the heli is rolling at the top of the loop, this says to me your entry into the loop was probably not level and is slightly askew.

Prior to loops and rolls, I always make it a point to ascertain whether the flyer is proficient at straight FFF.

Normally circuit flying entails doing some gentle turns at the end of a flyby to go the other way. Your first aerobatic runs are best done by using stall turns at the end of each flyby. Try to get your FFF straight first, if you are on a runway you should be flying parallel all the way (10 meters at your left and 10 meters at your right). Keep at it because this will serve as your springboard to do aerobatics.

If you are still doing a lot of correction (cyclic & pitch) during a FFF flyby, you need more stick time before attempting aerobatics.

Don't do maneuvers all over the place, you should be ingraining performing any manuever directly in front of you at the same place at the same altitude every time.

Once you have your "springboard", perform the maneuver you want once the heli is in front of you, loops are done headwind, rolls tailwind.

Loops should only entail flying straight into the wind, pull a little elevator (no aileron) with full throttle on the way up. Ease back on the throttle (and pitch) at the top of the loop and start putting forward elevator (and pitch) at the 9 o'clock position to exit back into FFF.

Another piece of advice, fly the heli, don't let it fly you. This means you should be flying ahead of the model. If what your're doing is just "correcting" for mistakes, this means the heli is flying you and you're just catching it.

Have fun!