Second, find examples in your neighborhood or area that you live.
Third, ask for estimates from contractors you might want to hire.
Fourth, find out about their work. There are reviews online, better business bureau, Facebook pages.
Lastly - do not choose the contractor by the price. There is some low quality work out there. Choosing quality for dollars will always help with the value of your home - and we all know that our homes are our best investment.
We go a step beyond in our interview process. Read the earlier blog post about this.