When choosing an interior decorator or architect, it's important to find someone who shares your aesthetic sensibilities. You should also feel comfortable working with them, as you'll likely be sharing a lot of personal information and spending a lot of time together. It's also important to choose someone who has experience in the type of renovation or design you're interested in. For example, if you're looking to remodel your kitchen, it would be wise to choose an architect who has extensive experience with kitchens. Finally, be sure to ask for referrals and read reviews from past clients. This will give you a good idea of what to expect from the decorator or architect you're considering hiring.
I would recommend finding an architect. An architect can help you design a space that is both beautiful and functional. They will be able to take into account your needs and desires and create a space that meets all of your requirements.