This is what I usually do with my horses and our show/dealing horses at my work.
Exercise the horse first to open up pores, if you struggle with mane pulling or the mane are very thick and coarse it may take a long time. Give your horse a mild sedative to prevent it getting too uncomfortable and fussy, or do it in a couple of sessions over a couple of days. Reward your horse for putting up with it after you're done, to add a positive note to the mane pulling.
Put water and the yank hard
Soak the mane in conditioner for 5-10 minuets and wash it out, than use a mane puller and take your time to pull the mane. I hope this helps
Do it just after exercising your horse. The pores will have opened due to them sweating and it’s a lot easier to pull manes. Put a little pressure on until you feel it give