I never liked Enchanters because their spells are easily countered by the Mind Blank spell. If that wasn't bad enough, Mind Blank lasts 24 hours and can be cast on creatures our than the caster. When I played a high level wizard, I would prepare it daily, and sometimes I'd save one for my dwarven fighter buddy, too.
But since you're challenging yourself to build a great enchanter, I'd prepare a counter to the Mind Blank. Greater Dispel Magic is an obvious choice, combined with Greater Arcane Sight to identify its existence on your target. Practiced Spellcaster (or any other feat to raise your caster level) would give you the added punch for your dispels to work. Heighten Spell for better spell penetration. Already mentioned are the spell focus and spell penetration feats, both really important since most your spells must be cast directly at a target.
Maybe you can find some synergy between quickened debuffing spells like Touch of Idiocy/Crushing Despair/Dispel Magic + enchanments for greater effectiveness.
Also, don't neglect the wizard specialist variants in UA.