What are top things do you look for when hiring someone to do a web design?

1) Portfolio
2) References
3) Price

I see you have already listed the most important items and in the correct order :)

Make sure that you completely understand any contracts, agreements, milestone schedules, pricing, etc. before you get into anything. I would recommend getting two proposals at least, just so you see what there is to offer from the competition.

Usually, though, you can't share proposals or any information about your business (other than a case study, maybe) with the competition. It's the rule :)