If you are looking to hire Drupal developer, at first you could consider to hire me, as your Drupal developer. But before that you must get trust.

It's important to trust your Drupal developer, before you hire him or her.

You should ask him/her to provide you with some recent Drupal work examples

Depending on your needs - do you need to build simple site or large scale project, you should ask to developer what modules he/she prefers, does it involves Drupal views? What about custom module writing? 

Does you need SEO as well? Drupal not always mean you will get great SEO. Out of box Drupal is not very SEO friendly. So if SEO is your concern, ask your Drupal developer what tools he/she will involve.

Performance is another, if not core thing to consider, choosing to hire Drupal developer. Your site should be fast as racing care.

Choose wisely your Drupal developer.

Best places to start with is official Drupal site, where are tons of Drupal developers eager you to hire them.

If you need some more guidance, drop me a message, and I will try to assist you, or eventually you can hire me for your next Drupal job.

I'm working core with Drupal since 2009. Since then I have built many smaller and larger projects with Drupal. My favorite combination is Drupal+Ngnix, I like to get my hands dirty by configuring servers as well.