Where do people look for established design companies? Share some ideas here, please.

Well. I can point you in the right direction. I won’t recommend any specific agencies even though I worked with some and I have favorites. I will do something better. Here you will find the professional UI design services . No, it isn’t a link to any specific design company. You will find a detailed guide on choosing those there. And in addition to this, there’s a list of companies you might consider choosing.