How do you get a job as a sissy maid?

Go online. There are websites devoted to matching people with similar fetishes (such as alt.com, to name one of the most prominent) if that is what you want. There are also sites of lifestyle dominatrixes and services who train and place sissy maids. There may even be someone local. But beware, many advertised "domes" are just providing brief fantasy service. You'll want to research their sites and chat with them about your desires to ensure you are getting someone who is committed to this as a lifestyle and can help introduce you to it.