I made a tool for pulling open the door panel. I converted an old large screwdriver by cutting a slot at the end, and gave it a slight bend. You could also use a piece of flat metal about 1/2" - 5/8" wide and around 1/8" thick x 9-12" long.
BTW, if you attempt to remove the door panel, it's a good idea to have some spare tabs on hand, as some of them may break due to age, or your technique.