I read somewhere that hair should be tied back during interviews so I popped mine back with a bump at the front (which I can now see was a little wonky!). I kept my make-up minimal, I wanted to look smart not overdone.
Again, jewellery was kept to a minimum, I wore my Wedding ring and a ring that I always wear on my other hand, my Michael Kors watch, and my Pandora bracelet. The watch hid my tattoo on my wrist, even though a lot of shops allow you to have tattoos on show I personally think that it is best to cover them up in interviews.
You don't have to spend a fortune, my whole outfit (bar jewellery) came from Primark, it looked smart and felt comfortable.
What is your go to interview outfit?