Just did this today. First, I got an old white t-shirt to use as my cloth, wet it, and gave the sticker and it's area a good wipe down. Then, I took a hair dryer and stood for about 2 minutes with it blowing about 5 inches from the sticker on medium heat going back and forth over it slowly. I then took a metal spatula wrapped in a t-shirt (credit card or just your fingernail will work too) and took the lettering off in one swipe through.
I didn't want to use any Goo-Gone or things like that - just water and heat. So to get rid of the left behind glue, I again heated the area the same way as before and did another pass over with the spatula/t-shirt combo. For the tiny bits that were left, I wrapped my thumb in t-shirt and slowly scraped away the rest of the adhesive. That got rid of my dealer sticker on the back gate.
Wet a clean part of the t-shirt, do a few wipe downs, and should look like nothing was ever there. Worked the same for my chrome hood JEEP emblem as well, just took a bit longer. Some people prefer to wash/wax before or after (sometimes before AND after) but I found that just doing a good damp cloth cleaning of the area before and after made for a flawless result.