Does anybody have tips or anything that would help me beat Elder Wyrm? I've tried many times but just can't seem to beat it. I'm almost at level 20 with most of the characters. Do I need to be at a higher level to beat it?

First and foremost, you must have Ally: any > Raise/Phoenix asigned to 2 or 3 of your guys and the gambit must sit at top spot. Next one should be automating curing spells, preferably for a Mage. Ally: any > Esuna to combat his Sporefall, and the rest should be items that remove status effects such as Blind, Confuse and Petrify. Oil you'll need to get rid of as soon as possible with Handkerchief. Try and keep Larsa alive so that your characters can benefit from his infinite supply of Potions/Hi-Potions/X-Potions.