I don't think anyone knows how to play Ryze really well yet, general trends I'm seeing:
His laning phase is different. He can't poke as well now, but he's still bad at all ins. What he can do is, if you find an opening where your opponent isn't behind minions, you can use your supercharged combo to trade with them and win, but you'll need to back off immediately when it's over, you can't really follow up on your trades afterwards unless your opponent is super low. He can also just stay far back and farm with Q, especially in tough match ups. I think new Ryze might be even more of a lategame champ than old Ryze was, so it's cool if you don't get ahead in lane as long as you don't get wrecked.
The other thing I think is really important is that now, even more than before, it's really important to have your combos down. If you screw up and just press all your buttons, you can end up doing way, way less damage. Once you hit five stacks, you just need to go QEQWQE... until the super state wears off. But you do need to pay attention to how many stacks you have and use your abilities in the right order to enter your super state. You can do it from as little as 1 stack if you have ult.
1 stack: Q>W>E>R (hit 5 stacks, reset Q) > QEQWQE...
2 stacks: RQW (hit 5 stacks) > QEQWQE... OR w/o ult EQW (hit 5 stacks) > QEQWQE...
3-4 stacks: QWQEQW... use ult first if you have it / want to
I didn't originally realize that you could use your super combo from 1 or 2 stacks. I think lots of people playing against Ryze aren't really thinking about that either. If you can take advantage of that you can get trades on unsuspecting lane opponents. But you need to cast your spells in the right order or your combo flops.