Here are a few tips:
If you're looking for a really gentle soap, find one where the main ingredient is olive oil! It won't lather as well as other soaps, but will be gentle enough to use on a baby.
If you want big fat bubbles, look for soaps which have a mixture of the following:
->Sugar. Yep! It's a natural way to increase the bubbles.
"Hard" Oils-A nice 'hard' oil will give good bubble action too.
->Coconut Oil
->Palm Kernel Oil
->Palm Oil
and for those who don't prefer Vegan soaps
->Lard!
Of course, there are many other things that can give good lather, so be sure to check that ingredients list to find out what is in it--and why! Typically, if you contact the soapmaker you buy from, they'll be able to give you the full information on what each oil brings and why they use it.
Soaps with deep color concentrations (like brilliant red) can bleed, especially if natural ingredients are used as the colorant. When using a brightly colored soap, stick to dark washcloths and save yourself some bleach!