1. You have 6 of each rune? If you were level 20 you would only have 2 Quintessence slots.
2. You have 0 resists past your base resists.
3. Your sheen increases your damage by like 100, and only on your auto attacks, your rylai's increases damage by even less, and the slow is only 15%, and then you get your boots last, and they are your biggest damage increase!

Your build needs major work, It doesn't look finished to be honest.