I'm currently a SAHM so I don't know how relevant my experience is, but my background is in banking/accounting and I'd recommend dressing ultra-conservative for any professional interview.
Suit (matching lined skirt & blazer or slacks & blazer) in one of your neutrals (perhaps gray/stone/brown/navy/black depending on your seasonal coloring)
Pantyhose with mid-heel closed toe pumps in coordinating neutral (nude/dark brown/navy/black)
Modest blouse in a flattering color (maybe a shade of blue if you want to appear nurturing/welcoming or a vivid red if you want to portray energy/power/confidence)
If your hair is longer than shoulder length, then wear it back (bun?) or pinned up (sophisticated)
Necklace & post earring (diamonds or pearls maybe)
If you wear a watch or belt, make sure all hardware (metal parts) are the same color of metal as your jewelry and any buckles on your shoes (silver or white gold if you have cool tone skin [winter/summer] and gold or bronze if you're a warm [spring/autumn])