Perfecting the Blow Out

I need help with perfecting the blow out and looking for some advice

I feel like i have the technique okay but im using Velcro rollers (and a clip) and they leave a dent at the top sometimes

Is this something im doing? Or is it the type of rollers - are there better rollers?

Any hair product recommendations (fine hair) Currently use a little heat protectant spray and leave in conditioner.

All other advice and feedback would be very much appreciated

My hair is fine