Use your regular recipe, but add some type of exfoliant to it. Finely ground oatmeal is a gentle one. Coffee grounds add more scrubbies. There are others, such as ground up luffa, even ground walnut shells.
If perhaps you do not have a tried and true recipe, you might want to start there. Go to soapcalc and play around with the oils and their amounts. It even gives you target numbers to tell if you are on the right track. And of course feel free to ask more questions!