MrAtom gave you good answers. 1-4 will become clear very quickly with a little practice, as your own preferences develop. 5 is harder to answer. It comes with experience. There is a limit to traction on any particular surface, and you'll learn to spot sand, gravel, oil, water, ice, etc., and your brain will automatically make decisions, but that won't happen right away. If you're lucky, assuming a little more traction than exists will cause a minor slide, and you'll feel that and back off. On clean pavement, with reasonably good tires, you can lean far enough to scrape the foot peg feelers. Not that you should try to do that.
