All raged player enjoy the comfort of the distance. As for Ryze, he is a nuker, should enjoy fast in and out combat style across distance. Anyone who wants to go in and fight to death should pick some other melee champ or at least a ranged carry.

Ryze has 2 spells having 14 second cooldown time. After 40% cooldown, and 2 later spell cast, the remaining cooling time is 6.4 seconds. Hence, if you dont get out after 1 second of nuking, you have to spend 5.4 seconds in hot zone to wait for the combo to be ready again.

Yes, there are plenty of people argue about the sequence and length of Ryze' combo, their argument is based on all spells and autoattacks take 1 second to complete. I dont believe it, so I do not max Ryze's CDR on purpose. Just happened to have nothing better to spend on masteries and items. AND, it still get me 34% CDR. You can finish up the rest with a pot or buff; but, I dont feel the need.

In most cases, Ryze's combo can take out 30 to 50% hp. If your opponent dont go back for healing, they risk death when facing 2nd or 3rd combo. This is why Ryze is so powerful, especially at lane phase after level 3 when Ryze acquired all 3 spells. Your enemy face the dilemma to get healing or staying. Most player would stay for you to kill as they dont know your potential. There are of course champions who can heal themselves, no champions are perfect.

There are people who argue about how squishy Ryze is at lane phase. I will explain more about what to do. In general, when facing a good player, farming as much is as good as preventing them to farm.

This is a guide for common player, I dont aim for super combos like other would told you to do which does make sense(but you do get to spend the magic time in hot zone). Instead, I rely on simpler combos that slowly chew up my enemy. EWQ as simple as that. a more complicated version would be REWQ. A long range version EQ.Or, the super killer which myself often forgot to use, F4QREWQ where F is my exhaust and 4 is Deathfire Grasp.

Considering QREWQ combo disregarding E's -MR
Banshee AAS FH ROA ROA - gives you a total of 1408 extra combo damage. (@ROA minimal)
Banshee AAS FH ROA ROA - gives you a total of 1553 extra combo damage. (@ROA max)
Banshee AAS WotA ROA Cap - gives you a total of 1544 extra combo damage. (@ROA minimal)
Now here comes my built
Banshee AAS WotA DG Cap - gives you a total of 1406 extra combo damage. (@ROA minimal)

The base combo damage is 610. At 30MR, gears including DG can nuke out a target with 2188 HP
but with out DG and cap, the best possible number would be 1630, which is a difference of 558 HP.
If you dont have DG ready, you can still pump out 1532 damage.

As a nuker, it is much better to get damaging/mana items than CDR. Besides, as Ryze, getting Crest of the Ancient Golem buff and 6 points spend in masteries would max your CDR. Now, you can practice the super super combo autoattack+4qreqw+autoattack blah blah blah after you get the buff. Anyways, I am not a fan of that; besides, that is not combo, that is melee fight.

There are times when you would need to hunt down a prey after an unsuccessful nuke.
The unsucessful nuke is one of the reason why I dont use item slow.
Secondly, Ryze does not need it to hunt.

If not autoattacking, Ryze will move as fast as his prey. Also, Ryze has rune cage to close the gap. Every time I chase, I will prevent autoattack and run before him in the direction he is heading towards. MEANING I would be closer to enemy base than the prey does. IF NOT it might be a trap. Why do you need a slow if you nuke? Why do you need a slow if you dont need to autoattack? Above all, Ryze still have a cage for chase.

Anyway, too much talking, all you need to do is walk with him for 5.4 seconds, and your combo is up again.

There are 2 situations at lane phase, 1. you can kill, or, 2. you cant kill.
If you can kill, try to conserve your mana, using autoattack to farm and spell to harass and damge. When the time comes, nuke him with your combo.

If you cant kill, either they can heal or very conservative. Use spell to speed up farming progress and keep farming. Charge your tear ASAP and get as much money as possible. WHY? going back for a recharge makes them seeing MIAs all the time as you get back for more mana, which helps ganking. And, you get more money. You will get plenty of time to teleport back when you keep on pushing to their tower. If they are too conservative, zone them out. Dont give them any chance to level up.

When it comes to tower, dont push too hard, let their tower take out your minions, it helps to preventing their champions to farm as well.

Initially, after getting first ruby, you have to decide to get 1 or 2 red pots. I get one only.
If I cannot keep up with my opponent after 1 pot is used, I need to consider the possibility I am facing a skilled player, and taking plan B instead.

After you get your advanced boot, I get boot of mobility, we move into Gank phase.
Gank phase might happend early if a tower fallen before you get the boot; where anyside can push minion wave deeper to gain more "traveling" time. You should choose to tower hug and farm for your boot. Do not go ganking with out a boot. As soon as you get your boot, you should start checking on enemy HP from time to time, as soon as HP level falls into ideal range, try ganking. It is very important to keep in mind, you only have one chance to gank, you can go MIA but never show up if you think nuke will not kill. Tho, it is good to force them to go back for recharge, but it is more fun to make a kill.

The situational items in this built are Rabadon's Deathcap, Banshee's Veil, and the boot.
These 3 items should be enough for you to get extra HP MR MP or armor. If not, please surrender. Swap Banshee's veil with Lichbane if you really want more damages with less protection. Cap gives most damage, but it is seen as a situational item; it is the last and most expensive item to be built.