Ok ive been in doing aoh's for a while and have noticed that a lot of people either dont know how to fight with their class or are really unprepared... im going to put what works for me in aoh as a witcher for my lvl 9-15 if anyone has any other forms or ways in which you fight and has worked for you please add :) also for the other classes go ahead and add your own help :)

witcher

equimpent:

all armor and weapons that increase will: try to get your tireless gladiator gear early on, (mixing and matching doesnt really help) strive to get your golden eagle armor pcs and your rapture, intoxication or persistance assesories and keep them up to date to your lvl very important!

belt:

1 endurance elixir highest color you can afford
4 life elixirs also highest color you can afford

secondary belt:

vampirism orbs works wonders highest lvl you can afford and as much as you can carry
nosferatus orbs also highest color and as many as you can afford
(optional) orbs of strength

buffs:
i prefer balms of life but its up to your discretion
rich soup

fighting:

i prefer to fight in attack position some people say to fight in mana position but for me i do more damage when i stick to attack position
ok very simple attack and use your vamp orbs as soon as you start taking damage keep it up until you can use your magic attack

use your magic depending on what class your up against:

bezerker use earth magic 70% of the time you will crit them for 200+ depending on your armor and accesories.. furthermore if your will is higher than thier intuition thier chances of them criting you are about 10% hence you should rarely if ever lose to a zerker (of course if they have more armor pcs and higher acessories dont expect much)

palis use chaos magic 50% of the time you will take away their health and add it to yours and is the one that does most damage to them... remember that as witcher we are weak against palis so dont feel bad if you lose to them let the zerkers in your team take care of them.. one of the ways ive seen some witchers increase their chances against palis is to get assesories that increase your intuition but take into consideration that it will lower your will and your chances of beating a zerker its up to your discretion.

witchers you'll be pretty balanced off so its up to who has better armor accessories and more luck.

hope it helps and if you have any more suggestions feel free to add them or any corrections are welcomed and if your a different class id be great if you can add your help.