I would like to add a couple of points that may add value to some of the posts on this thread. If you are an active rehabber or rehab and holder as we are, it is really important to have more than one good GC in your arsenal. Good GCs are always busy, and it's always hard to line up scheduling to work out just right, no investor wants an empty house sitting and not progressing because their GC is busy working on a big job for another investor. So, to that point I am always upfront with the contractors we work with that scheduling and accuracy are paramount. I spend MY time doing the detailed write up exactly as @Matthew Paul stated above. The devil is in the details, contractors love it when they don't have to spend a lot of time describing what they will do on the project. My favorite proposals are when the GC simply puts a dollar amount next to each line item on my proposed work sheet. They are only estimating how long the labor will take....keep it easy for them, simple. It is not their job to tell you how much the materials should be, that what the Internet is for, we can do that in our sleep. I try to get 2 proposals, and I do not pay for the proposals. I ask the GC for a fair price, if I like it, we do business, if not, I do not haggle with them, I move on. There is where the trust factor comes into play, I have to trust him to be reasonable and fair with me, because if I don't trust him, nothing he does or charges is going to be adequate ( in my mind), it just cheapens the relationship. The times I have been screwed over hailed from skipping the 2 estimate step....we all know sometimes it seems like you just can't get an estimate for a project. When that happens, take my advice, drop back ten, take a deep breath and come at the project from a different perspective, start over with finding the right contractor for the job.
Regarding the time spent doing walk-throughs with GCs....I used to think it was just a waste of time, but I soon realized that when going through a house and having a GC realize your vision, here is where you will find their creativity and perhaps a vision much better than yours. They have to understand where you are going and what you are trying to accomplish. You will quickly find out if you can work with this person. I have walked out of appointments knowing I wanted to work on a project with one GC over another, before I ever saw a price. It's a strange feeling.
Finally, pricing...leave some meat on the bone....we all have to eat, so does your GC. After all you want him to hurry back next time you have a job for him.