Welcome to the "cleaner" side of modeling Rob.
I'll try to help with how my son and I work on ours, we work with enamel paints by the way.
Before anything, I wash all parts with mild dish detergent, rinse, dry,
and then just before working on it I wipe it down with Isopropyl
Alcohol.
The first thing I work on is the body and any parts that go with it,
such as hood, mirrors, spoilers, etc... I test fit the parts, sand or
file for a clean fit (don't like it when the hood sticks up LOL). I
check for and fix any imperfections (spot putty if needed) and cleanup
flashing of course. I carefully and gently wetsand the plastic with 400
to 800 grit (whatever I have kicking around). I then primer all the
pieces as they are spread out seperately. Once dry, I wetsand again,
check for imperfections and then wipe down again with the Alcohol. I
then give it 2 to 3 mist coats of the final color paint and set it
aside to dry until another day.
I'll glue some parts together before painting, such as the engine
halves, heads and anything that will get painted the same color or that
I can get the brush around. I'll paint the glued motor pieces then set
them aside to dry. I'll paint the undercarriage and suspension pieces.
I'll paint the interior tub, pieces and detail the dashboard.
After the paint dries, I'll start glueing things together.
Back to the body. I wetsand again but with 800 to 1200 grit if the
finish is fairly smooth, then spray my next 2 to 3 final wet coats of
paint. I don't install the windshield until after I'm done painting and
detailing the body. When the paint is fully cured (I wait at least a
month) I'll use Mequiar's Scratch X if needed and then Mequiar's Gold
paste wax.
My son preferes to leave most of the parts attached to the sprue while
he paints them. He found it easier than using tweezers or toothpicks to
hold some of the smaller parts while brushing on the paint.
As far as what paint to use... I've used all types of enamel paints on
my models over the years. When I was a kid I used some lacquers but
they are more work. Two important things to remember - If using a
non-modeling paint (one intended for our plastic kits), use a good
primer coat to seal the plastic. Pick the color that suits your needs
or fancy and spray away.
I matched some factory colors using those spray cans of Dupli-Color
touchup paints. I keep my eye out for colors at Wal*Mart and my local
auto supply shop besides Testors LOL.
Hope that helped get you started.
Maybe I should of had my morning coffee first?