1. I start with a skeleton (a preliminary sketch). I'd say it's the main composition. Not always, but usually this is the case. Once I start applying paint, it can go anywhere. Sometimes, I'll take a snapshot of the canvas while I'm working on it and play with some of the color palette in Photoshop, and sometimes I don't. Either way, it's not going to turn out exactly as I planned. There is always room for intuition as the process takes place. There has to be. It also depends on the subject matter. For a landscape, I might begin with a real photograph, but it's never going to look like that photograph because it's a fantasy. The fantasy comes alive in the process. I have no idea what is going to happen in that process.
2. I don't believe in the right brain-left brain thing. I don't have the reference to link to off hand, but I have read somewhere that it's been scientifically studied that this theory is not all it's cracked up to be. I can look for it because I probably sound like I'm being contrary without a leg to stand on. However, there is a drawing exercise I use that was originally based on left brain-right brain and I use it to this day. I don't know if it works or not, but I use it anyway.
3. I do know there must be something to parts of the brain that are centered on visual creativity and another on problem solving because I experience it myself, like when I am doing lots of computer stuff, then have to go paint. It's like two different "sides" of my brain that have to "shift" and they are not the same kind of creative mindset.
4. I was originally left-hand dominant, but had a accident to that hand during the time I learned to write and had to start using my right hand. I write and draw like a lefty, so I have no idea (if the right/left brain thing is true), what that might mean for me.