You don't if you have olive skin or genes from a darks skined nationality. I wouldn't go out without sunscreen if I was fair. If you mean a tanning bed forget it. Too dangerous in my opinion. Fake tans are probably the safest way if your fair. But then again they have chemicals. You could try a mineral bronzer dusted all over exposed skin. But then again that may come off on your clothes. Probably a tinted moisturizer may do the same. If you want natural tan then probably blocks of no more than 30 minutes in the sun with a uv sun screen.