You can get really fancy with your bath adding in ginger, baking soda, essential oils, but good old Epson Salt usually does the trick for me. The process I use is 2 cups of Epson Salt with Lemon Essential oil and maybe some lavender. You should always shower after to rinse off your skin. And know your skin may start to sting or itch a little if using oils. I have never had that experience when using straight Epson salt.
I also do Epson salt baths when me or my kids start feeling bad. Usually wipes those nasty germs right out.
I do have a favorite oil company and I do not get any kick backs from them*, I just like them. Native American Nutritional. I will also buy Oils at Whole Foods in a pinch but only the straight oils, I get all my blends I love Aligning and First Aid.
I also want to make sure you are taking in minerals. Although the minerals from the salt get into your skin you need to keep your mineral up for the health of your body and successful losing.
*I am not opposed to kick backs just do not get them. ;)