How to determine ARV and rehab value

[Colin Carr]

Hey All! So I have very little background in construction or house repair. I also just bought my first duplex, but am new to the game. So here are two questions that have been bothering me and are making me feel timid about buying property that needs repair. 

1. How would someone like me, with no repair experience, go about assessing how much it would cost to repair a place. 

2. Once I have the value from number one, how then do I assess what the value after the repair would be?

Basically I'm looking at trying to get the two fundamental inputs to the 70% "rule". I'm sure some people will say to contact a contractor and a real estate agent. That's good to hear, but is there anything I can do myself? Does anybody have any good resources to educate myself on the cost of rehabbing houses? 

And I'm also in the Denver area, so if anybody has any suggestions for a good real estate agent knowledgeable in real estate investment and suggestions for a good contractor I'm all ears! As always, thanks.  

Colin