Can you supply references, and check them out/call them. May want to also check if it can be built to CODE PLUS, which is a step up from standard building codes, may be worth it.
how long in business, referrals from trade professionals, licensed/insured?
does their portfolio illustrate the ability to design to your style request? budget?
BEFORE you ever get to interview stage, you should have found him/her based on references from folks you know and trust who have tastes similar to your own
The most important question to ask before interviewing an architect is if you need one.
I have seen many occasions that a homeowner would have been better served by a design/build remodeler rather than an architect.
Are you planning to build a new home? If so you may need an architect. If you are planning something short of a new home you may be in for a surprise when you look for a contractor to build your newly architect planned project.
Some architects are great an planning something you can afford to build, others are great at charging to draw plans illustrating your dream with no regard to the ultimate cost of construction.
I am not trying to put down architects. When you need one, no one else will do.
Design/ build remodelers are experts at all aspects of remodeling and home additions. They are very talented at design and developing a project to a budget. They also have a vested interest in developing a project you will choose to purchase. Not all, but many architects have a vested interest in drawing plans that you are willing to purchase. Chances are this is not intentional. They just don't know as much about construction pricing as they might think.
My suggestion is if you are going to hire an architect, ask around for a personal recommendation for one who has a track record for knowing how to project ultimate costs of construction.