New to painting.

I recommend Rust Oleum Painter's Touch 2x Rattle Cans for a good all around spray paint. Spray paint will look better than hand painting. I just started topping it with this clearcoat:

Looks like a good first step! I would recommend using spray paint if you can get some. It's pretty easy to make a DIY spray booth with a Amazon box and a fan around you. The cars take so little paint it's not difficult to do inside or even in your garage. You'll get put more consistent results than using acrylics and hand painting. Although brush painting will be great for any graphics/pictures you want to paint, but for full washes, spray paint's the way to go.

Check out the Paints & Decals section of the forum, there's lots of articles about techniques and types of paint to try.

There are plenty of You Tube videos explaining the techniques and processes of painting Hot Wheels. You will find plenty of tips and most of the tools and paints you could use.

In the mean time you could experiment with paint pens. A relatively inexpensive option that will give you a  variety of colors to work with.

There are many videos on this as well as online articles, but here are some high points. You can certainly use commercial paints that you can find at your big box stores such as rustoleum or krylon. I feel these tend to go on a little heavy, but they can work fine. However, pay strict attention to the painting rules on the back of the clearcoat. Not following the application times exactly can result in a popcorn or cracked finish.

when I'm looking for a top notch finish on a car I usually move to Tamiya paints which your local hobby store should have. These paints have great color density and coverage and go on very light.

I almost always prime with a flat white before painting. getting a good primer adhered to the original surface is incredibly important for a good paint job. And I have to say this is one area where I do recommend a rustoleum product which is called - universal bonding primer (flat white). the other important part is starting your paint job on a white surface will give you true colors.

There's one more tip and that is if you prime the car white you get instant easy racing stripes.
very easy, prime the car with flat white and wait 45 minutes. With super clean hands apply something like 6 mm masking tape making a racing stripe on top of the white paint. Now let's say you're gonna paint this car dark green, which you do paint it dark green. Now this has to be thoroughly dry before you pull the masking tape so that's about two days. Then slowly remove the masking tape, pulling straight up, and you should end up with a nice wide white racing stripe

The BMW I'll re paint for rally uses.

My rally colors ala rattle can

This team is at the same race as Abby. Used a paint stripper to take the original paint off. Primer with Rustolem bare metal primer flat white. Dry for 12hr, second primer coat, dry 12hr, Top coat is a White Semi-Gloss, dry for 48hr, apply decals and gold trim paint, then clear coat.