You can get the vests at WalMart or any sporting goods store.

And just go and sit for about 15 minets to 30 minets at a time.
Sit next to a tree or bush to break up your outline.
And camo helps a lot.
Use hunter orange if requaired by your state.
You want to hunt legal and be safe.
If a squirrel gos around a tree on the other side just be still and throw a rock or something on the other side and the squirrel will think it is you and come around to your side for a shot.
You can also hang your coat on a tree limb and walk around the tree the squirrel will think your coat is you and give a shot.
Good Luck.