When you hit 6 you can solo drake EZ. You just need to use ult and spam spells. Your ganks is know also better than the early game.
You would have 3000+ mana. This gives you tons and tons of damage. You would not expect the Damage!
If you want to engage, you use ult for ex speed and also couldown on spells. This will do much damage and if youre getting low, start to fall off when your team finish YOUR job!
This is a very efective way to get higher in ranked. With this help i give up one thing for you to do. Do you have the skill in ryze to main ryze and get higher up in ranked. That is up to yourself.