Give it a stir every day. Let it work for three or four days, stirring it each day. When the smell is yeasty and sour, transfer it to a clean container and refrigerate until you're ready to use it. The wild yeast in your kitchen just may not want to cooperate or there may not be enough present to start the starter. If the water in your area contains chlorine, use distilled water or tap water that you've allowed to set out for 24 hours when you make your starter.
Chlorine can put a lid on the development of yeast.
Use only glass, glazed ceramic or crockery to hold your starter. No metal or plastic. And start clean, and keep it clean. Every so often, you can dump the starter into a temporary container while you wash its permanent container in hot, soapy water. The container should be covered, but the lid should not be air-tight.