>>> 1, which brand/type of primer is good
you can get prime from either Home Depot or Benjamin Moore.
>>> 2, which brand/type of paint is good or that you recommend
I prefer Benjamin Moore mid grade latex based paint.
>>> 3, which paint is better, oil based or water based
Depends where you use it. For exterier you might want to use oil based. Interior, I use Latex based.
>>> 4, Is sanding required after primer and 1st coat ? If so, what type / number of sanding paper is appropriate
Most cases, you don't have to sand.
>>> 5, Since it is winter now, do I need to turn up the heat or any fans to help the paint to dry ?
It doesn't smell too strong, latexed paint, just go ahead start painting.