I usually check to see if I'm dreaming once I stop feeling vibrations and I pretty much always am at that point. Some people use a fan/AC because they stop hearing the noise of it once they're in a dream. I like to check by doing an epiglottis block RC, where I basically either try to breathe through my mouth while it's closed or I slightly tense my neck muscles to block my throat hole, then try to breathe. If air gets through, then I know I'm dreaming. There are a ton of different ways to check, a lot more than I listed. If you want more advice on WILD, you should check out Sageous' WILD class. He is awesome and very knowledgeable, he's helped me and a lot of other people get better at WILD.

Here's a link: WILD