Experiences/knowledge for estimating rehab/flips

[Miles Fletcher]

Greetings!

Due to being in Denver, I've seen that my market is not profitable for cashflow rentals, but has opportunities for wholesale or flipping. 

What experiences and knowledge would you deem necessary in order to go about estimating rehab costs in order to determine if an opportunity is, in-fact, a profitable deal? 

I would like to raise more capital this way before investing in rental properties out-of-state.