Alright, my advice for the most powerful build possible? Ditch the bloodlines you've got now, go Arcane. Be a human rather than half-elf, take the human favored class bonus that gets you an extra spell every level. Make sure to grab good low-level debuffs like Color Spray and Grease. Fly is good if you have room for it, and Haste is fantastic if you are in a party.