This build will give you great sustainability with enough health to even kill your enemies. If you're fighting a losing battle, you'll at least alert your teammates who can pick up the kill for you. With two warmog's, a spirit visage, and a guardian angel, you won't be a quick kill. You might even solo out a turrent and maybe save your teammates with your abilities and still being able to survive running away. Archangel guarantees that you won't run out of mana too quickly and provides a lot of ability power that will go well with your spell vamp.

I've taken Cripple because of Exhaust but you can use it on something else if you knwo you won't take exhaust. The others are recommended in offense. On defense, once again I've taken the heal mastery, but if you think you'll take fortify or cleanse then suit your own needs. The only reason why I took Ardor is because it seems better than dodge chance. You really want that Tenacity.

Simple, my runes are based around my abilities upgrading mana and mana regen along with magic penetration. if you feel like the mana is an overdose get rid of the glyphs and fit it to your own need. The quintessences should help you stay alive throughout the game.

All of your abilities are pretty good but E is great for level one. Scout out the brush and use it on gank lanes to prevent dying. A stun and a slow are both valuable so basically get your abilities ASAP. E is your strongest one and pretty good in dealing far range damage and getting kills if you're lucky. (Got a double kill with this once.) Upgrade W again and then R in case of a team fight. Try to max E and then keep W and Q close levels with each other while upgrading R as mush as possible. W should be a higher level than Q since a stun is usually better than a slow. If you're having lots of team fights then I recommend getting your R pretty soon.

Heal and Exhaust are there because of the masteries. You might want to get clarity since Maokai relies of his abilities for damage more than his basic attacks. Flash>ghost. If you have a feeling you might do bad early game get a fortify.

Generally follow this build. What you really want to do is be flexible and get items based on what you need. If you're dying a lot, get Guardian Angel over Warmog's. When building for Warmog, Giant's belt and regrowth are tied. If you want to save gold, get Morello's Evil Tome and then sell it to get Archangel, but Morello can provide as a substitute for Arch and might be better if you can't get archangel high enough on it's passive.

As a tank, you won't be dealing as much damage as your teammates so try to help them escape if they need too. At base use your abilities to help Magical Sap come quicker. When chasing an enemy you should especially take a different path to stun them. You can stun over cliffs, etc. It can really help your damage dealing friends catch up and finish them off. Then play defense and save their lives. One of you is more than possible more of the,. They don't have the sustainability you do. Farming obviously get as much minions as possible when using E. Mages should be easy to kill and if you really want to finish them use an Q or simply attack them one by one. When dragoning, use all your abilities and when low on mana use only E. Does the most damage per mana. If you need to run try using W and Q if you have to.