I would do it myself.

There is a nationwide web site called NextDoor.com which is kind of like a combination of Craig’s List and Fluther. If there is a Nextdoor group for your area, you can join for free and then ask questions on there for recommendations from people in your area for decorators, restaurants, etc. It’s quite useful for local news and recommendations.

Consider going to some local decor stores and ask for recommendations. And then ask people who respond for a portfolio of their work, and for recommednations from former clients.

I would plan it myself, but I’d get help on physically pulling it all together, starting with a new house.
When I got out of the hospital in late 2012, after suffering from lingering memory loss, I didn’t recognize the house I’d lived in for 12 years. I walked in, didn’t recognize anything in there either. But I do remember saying to myself, “Wow. Someone has nice taste!”

If cost weren’t an issue, I would look at examples of the design I was interested in. The designers will be credited in those publications and I’d reach out to a few of the ones I liked the best, pitch them what I was hoping to achieve and see if they would be interested in the project.

I’d begin by getting recommendations from people I know who have nicely-decorated homes. Then, I’d do as @janbb suggests and go to NextDoor and other community message boards.

I don’t trust online reviews; people get their friends and family to post glowing remarks. Also, a portfolio can be easily faked.

I wouldn’t even consider anyone who demands a fee for an initial consultation. The person should be wiling to stop by, see the place, talk with me, and determine if we’re a good fit. I don’t expect any freebie ideas whatsoever, but I won’t let the meter start running until we’re actually working together.

During that introductory meeting, I’d get a sense of whether the person relies on the newest trends and colors. That’s the difference between a clever, creative decorator and one who’s fair-to-mediocre – the lesser version simply mimics whatever’s currently found in magazines and showrooms and leans on Pantone’s Color of the Year. Today’s hot fad quickly becomes tomorrow’s stale, dated look.

A talented individual will work with my own space, to create something that reflects my tastes and stands the test of time. Also, form has to function; a good designer won’t recommend anything that’s impractical or doesn’t fit the homeowner’s lifestyle.