In-short this build will provide u with a solid power-house robit that keeps going and going and going and going and . . . going
( /\ no period, never stops)

When I first started playing this game I wanted to spend my ip wisely; I wanted to buy a badass, fun, hard to kill champ; I saw that in Blitz. What makes Blitz badass is his abilities, I LOVE surprising an enemy by grabbing them through some trees or while they are about to get away and are on the run. What makes Blitz fun is that his grab is a skill shot, and makes it a bit challenging especially since my laptop overheats and I usually have an FPS of about 10. And I think the last part is self-explanatory; he is hard to kill because he is a tank.

Preparation:

Masteries for most of my tanks are set tank first, then ability second. Hence 9/21/0.

Spells are Fortify and Flash.
When I play Blitz I like to piss people off, get kills early, get people to rage quit, and be able to solo a lane; Fort allows me to do this with ease. Now this does not mean you are the best at soloing and should go mid; a ranged champ that goes mid is a lot harder to grab than a melee champ. A lot of the times early game I will sit back and move around to wait for a good grab then power fist in the turret's range so I can then Fortify and get a nice easy kill which also has splash damage from the masteries. Fort has a long cooldown though so use it wisely and try to get as many kills as possible with it. Also don't forget to try and grab your enemy before enemy minions come into the turret range so that they are targetted and not the minions, or right after the minions are about to be killed off then hit them with power fist and fortify.
I also like to chase down enemies fleeing with low health, get into the middle of a battle, or simple escape a battle with low health; Flash allows me to do.
If you just refuse to use fortify, thinking that you really can't use it in enemy territory and that you are wasting a spell by needing opponents to be winning to use it, then I would suggest Exhaust. Exhaust can be used on offense, escaping a death in a battle in the middle of nowhere, and can aslo be used to slow your target once grabbed into your turrets hot zone to maybe get one more hit from the turret on them.
I don't believe in ghost since you have an ability called Overdrive which is just like ghost.

Runes aren't necessary but if you don't think you'll be buying a new champ soon then you might as well buy them since they help you more than not having them, but be careful because some are better deals than others.
Now I don't have all of my rune spots filled, but this is what I would like to have. Extra ability power, the best deal is buying the quintessences. To continue ability damage buy the magic penetration in the Greater Marks category (best deal). Now here is where you can go two different ways you can max out on mana buying both the seals and glyphs in total mana or you could buy just the seals in mana and cooldown reduction in the glyphs. The best deal for mana is in the Glyphs but the best deal for cd reduction is also in the glyphs. There is no point in buying cd reduction in something other than the glyphs section though since less than -6% reduction will probably have little effect.

Playing the Game:

In beginning part of the game before you buy your glacial shroud you're gonna find yourself out of mana, so buy a saphire crystal and then mana potions when needed, you shouldn't need health potions at all. In the beginning of the game I like to tell my lane partner to let the other team push and get ready to stun if they have one. This way I can get my fortify use in and get some easy kills without losing a chunk of health so then we can chase down the other enemy with full health. I do not just turret hug though, I wait in range of enemy minions getting xp and wait to grab someone into the turret zone until I have my second ability powerfist which will keep them in range for a while longer.

I do not level powerfist again for a while once I get it on level 2 since all leveling it up does is reduce it's cd. while leveling other abilities get more benefits like damage or speed.

Since you will be playing a patient early game you will not really need boots so buy a sheen to give you extra damage in your 1-2-3 combo of q e r abilities. Before you complete youar trinity force buy a glacial shroud which will gice you cd reduction and mana; from now on you shouldn't need man potions and you should be easily able to run with overdrive from lane to lane helping teammates gank or going to kill some minions with either your w e r abilities. Your r ability can help you farm minions easily getting you loads of gold (look for bunches of enemy minions run in the middle of the group and unleash a static field ability on them); you'll find it will cooldown pretty quick.

The Build:
The most important stuff that the Trinity Force gives you is Health, mana, ability power and attack. To help farming the minions that have a little more health when a static field is used on them buy a sunfire cape, which also adds to ur health. Next is a bit of magic resistance since that is the weak point of this build, so buy mercury treads, you don't need swiftness you have overdrive for swiftness. Frozen heart will provide you with more armor and better cd reduction, plus a lot more mana. And finally buy a guardian angel for another life armor and more magic resistance. After that the game should be over but if it isn't you have one more item for your choice I would stick with either frozen mallet, force of nature, warthmog, rylai's crystal scepter, another sunfire cape, or maybe randuin's omen. What ever you want to mess with or think the battle calls for. Just try and stay in the Health, or Health regen section of items; the only thing I would consider outside the Health section would be the manamune since it would convert all that mana into attack damage, but the manamune is a last item only if it is bought for Blitz.

GOALS:
Hopefully this build was short enough for you to read, I probably left stuff out about how to play but all it really takes is practice. What you should aim for is always having over 10 assists, 0 - 5 deaths, and anywhere from 5 - 15 kills. After a while hopefully you'll be able to know how much damage your 1-2-3 combo will do on an enemy and whether you should grab or w8 and where you should aim your grab.Be ferocious and gain rep for Blitz!