Well here's a short list of some of the things you'll have to do in no specific order. Keep in mind, this isn't a complete list.
Make sure the tires are filled and aren't leaking.
Grease the mechanical parts.
Check all the wiring, replace any old wires.
Check and clean the filters.
Check the suspension, make sure it'll hold up.
Check the lines (like the fuel lines) replace any old lines so you don't have any leaks.
Pull the spark plugs out and clean the terminals with some sand paper, maybe take them to an autoshop to have them sandblasted.
Once you think it's ready to go, put a very small amount of fuel in it and just see if it starts up. If it does, then you're good to go.