Do you know how long it's been sitting for? Depending on that you might not necessarily need to drain the gas, though it also depends on how full the tank is. I'd probably do battery, oil and fresh gas first to get it running, then plugs, etc to get it running nicely. Well, as nicely as possible for a car that's been sitting unloved.
Don't forget to check the tires, if it's been long they're likely cracked and unsafe at any considerable speed.