As a THM who solo/duod from 10-50 I have one bit of advice that will save you eons of time.
Find something weak to lightning 4-5 levels above you (I think there are some rank 44-45 Toxic toads near bald knoll) and start casting Thunder > Thandara like it was going out of style. Can easilly chain 5 if you have enough MP, only issue is resists can often make or break your chain so good gear is a must.
