Veigar is an amazing burst champion, but he is very squishy.
this build helps slowly build a tanky and not so 1 shot-able version of him for support.

Since he scales endlessly off of poking, you may not be strong or tanky super early, but late game, you should be able to deal damage and take it.

You make a great detraction as the game goes on. I often find myself getting ulted by a Rengar or jumped on a Kahzix before my adc. "Your the squishy support who also does damage, get the out of the way, and the adc is next." However, when they go to hit me, and only 10% of my health is gone after my 2nd item, they get confused, either running or continuing there attempts on this builds life. The end result is a lot of gray screen simulator players.

This build isn't 100% fool proof, but it sure as hell is fun to play.

So, just cuz your going tank doesn't mean you wont hurt.

Early game, your goal is to stack both your passive and grasp. This means poking and auto. For starters, throw down some Es and auto who is in them when its safe, and if your adc is okay with it, poke full health minions to keep your grasp stack up.

When you hit Level 3 is where the fun begins. back and grab what ever you can, refill your mana, and run back to lane. It's now safe to to engage. Attack, Zone, Auto, have your adc poke in.

By now, you may have noticed you might be more wanting to stay back, that is also okay. Just poke when ya can, you can relax at this point, or wait for them to go in on you. Right now, you build your items and your stacks.

At this point, you should be hard to kill, and still deal some damage. You should be roaming about, and helping where you can.