First - invest in a big fat felt tip marker. I hate signs done in ball point.
Check to see if your newspaper has free garage sale signs when you place your ad. Ours does.
To hang clothing, try a rod between two ladders. Also helps in hanging other stuff.
Make sure all electrical items work or provide an extension cord so things can be plugged in.
Plenty of room to park without blocking the street? That said, there will be one or two who will park willy-nilly no matter what.
I don't know how many folks park in the drive next to our Lapidary house when we have our sale even though we have a big parking lot 20 feet away!
Condsider a lobotomy... (Egads. I've been reading too many posts by Ryan!