What you will need:

1. Two or more friends
2. A boat (and a nice open spot)
3. A Scribe (+ blanks and summon demon regs)
4. A ton of aids 

There are few different set ups for resist. You can have 1 Mage summoning and 1 healer, or 2 Mages and 1 Healer or 2 of each. The last one is of course the best (one healer and one mage would work as well, but slower). You are not likely to die and you will have a good solid burst with 2 mages casting demons. It helps big time if your friends have multiple accounts (my friends do). When I work burst with my crew they run two accounts, one for healing and one for summoning. If your friends only have one account (like me) then you can just do 1 healer and 1 mage. I would strongly suggest using a healer (or two), otherwise you will burn up a ton of regs healing/curing yourself. Ok now, about the boat. Park it on the shore just like you can see in the picture, make sure all the demons you summon can cast on you. 

You will also need a scribe to make you demon scrolls. "Scrolls? wtf?" ...yeah scrolls are way better, first of all the scribing success rate is roughly 50%, so out of 100 blanks and 100 each summon regs you would get around 50 Demon Scrolls. Even with GM Magery you would still fizzle more than 50% of time if you were to summon them using regs, so the cost is about the same. Moreover with scrolls you always have a consistent rate. 

The set up in the picture works great. You have two healers running a UOA Macro to heal and two mages summoning demons. 

This might not sound like the easiest way to get your resist up, but believe me it is worth it. The guy who is getting resist in the pictures (Lumpy aka Purple Llama) got to 90 from 60 in about 5 PHs.

Some Tips:

1. Bag all your stuff (you will loot it faster)
2. Carry Potions (from 5 - 10 GH and GC)
3. Carry a lot food

Pic #1 - Before

Pic #2 - After