Ask them what they have done before. First of all, years of experience is good to have so you may want to strive for 5-10 years instead of someone with 2 years.

Ask them what they have done before. First of all, years of experience is good to have so you may want to strive for 5-10 years instead of someone with 2 years. You can then ask if they have mentored others before and how they think about best doing that. Also hear if they have been the lead developer in projects before. Just some ideas.