Everyone has their favorite method. I have a little bag 2 inches by 3 inches with about 50 ft of string tied to it.  I put a rock in the bag and throw it over the limb.  Then tie it to the line that will go between the trees and pull it over.
I use Ronstan 20 blocks
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They have very good bearings and the line will siphon out from its own weight so tie a stick to the line about 15 ft from the end. 
I use a small line like Solotripper to go through the pulley system. My line is smaller than Solotrippers and not near as strong but will easily lift my 190Lb off the ground. He uses a piece of PVC pipe to protect his hands I use leather gloves.  I suggest you use some thing because rope burns hurt.
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MagicPadddler