Always have at least eight to nine Auras in your arsenal, or else you will be lacking in Aura at the beginning of the mission and waste skills. Also, have a balance between long, medium, and short range attacks. Have perhaps three long range, four medium, and three short attacks. Make sure you are equipped with enough defense skills, especially low cost skills that you can use to block attacks that do not cause damage. Finally, make one of your two classes the Nature class so that you can use healing skills like Healing Water.