What skin type do you have? People with dry or sensitive skin types may prefer a creamy cleanser that adds moisture to skin while cleansing. Liquid and gel cleansers are best suited to oily and combination skin types. Skin care expert Paula Begoun provides an excellent article that explains how to determine your skin type.
What issues you are trying to treat? Some cleansers contain ingredients to help treat acne, even skin tone and reduce the size of pores. If you have conditions like eczema, psoriasis or allergies, you're better off with a non-irritating cleanser formulated for extremely sensitive or damaged skin.
Do you prefer natural or eco-friendly products? There are no set guidelines to govern what counts as "natural" or "eco-friendly," so customers really have to do their homework in this category. Look for products that contain recognizable ingredients and are free of mineral oils, parabens and other chemical preservatives, coloring and fragrances. The Environmental Working Group's (EWG) Skin Deep Cosmetic Database is an in-depth resource that discusses the ingredients used in various cleansers, as well as their environmental impact and whether they're tested on animals.
Cleansing waters use tiny oil molecules clustered in water to cleanse makeup and dirt off your face. You don't have to rinse cleansing waters away, but you do need a tool like a cotton ball to apply them -- and although they received a lot of hype a couple of years ago, they're just as variable in their performance as any other type of cleanser.