Choosing your contractors & estimating rehab costs

A very common question around BP Nation is how to choose contractors and where to find them. Moreover, so many newbie investors ask how to estimate the costs to repair the property to bring it to the highest market value possible. So I would like to start a discussion here to address these issues and do so by asking the you all these questions based on the following criteria:

Criteria #1. You are a newbie (never flipped a single property before), your feet are wet and you have flipped 1-2 properties, you are a novice flipper and have flipped 3 or more.

Criteria #2. You have a job and can not be at the flip too often (especially during the normal construction hours), or you can be at the flip as often as needed.

Criteria #3. You act as the owner builder and hire each individual sub contractor or you hire a general contractor.

Based on the criteria above, how did you experienced flippers select your contractors and estimate repair costs vs how do you newbie and novice investors propose to do so?

Let the games begin . . . .