The basics - Poke

Always poke with your AA and Q, earlygame you can get someone below half health in the first 10 seconds of laning and secure yourself firstblood when you hit lvl2.

The basics - Rotation
ALWAYS ALWAYS ALWAYS Q FIRST!
when knowing how your rotation will be, ask yourself this - are they going all in on me and am i close enough that E will bounce off me and back to him a bunch of times.
Are they going all in? freekill for you! QEWQ mash that combo as fast as u can, take a step away then move back in for another Q, dat nukka should be dead
Are they gonna run as soon as i'm in range? Get close enough and QWEQ that'll give u enough time to finish your rotation although it does less damage.

Some quick mo****in tips every ryze needs to know
Always Q first because it lets you Q again for a 4 button combo instead of 3
If you press R right after you press Q, your Q will get the bonus from your ulti, traveltimeop
Never ever upgrade the tear into archangels/manamune until it's your last item
Harass a ton with AA and Q, it does wonders
Never be scared of getting ganked, you are ryze and you fear nothing, 99% of the time you can net yourself a double kill
Ryze is a tank and a AP assassin, you can and should be the one to initiate combat