I loved building models years ago but I was never great. There are more products out there these days so hopefully it will be easier. My first attempt is going to be weathering an RC tank - VS PRO 1/24 M1A2 Abrams, which came "pre-painted" (as part of the manufacturing process). I want to make it better and relearn how to paint in the process. What would you recommend to use as a primer or varnish or sealant as a start point to build on ? I have been reading and watching tutorials so I think I know what to do after that. Thank you.

It is always good to see someone return to the fold and take upf sticking plastic together again.

When it comes to painting a good grey undercoat is hard to beat with various manufacturers producing their own versions. Many modellers buy car paint rattle cans, but make sure you do not purchase one that will attack the plastic.

Welcome back to the hobby Scott ! There have been great advances over the last 20 years in scale modeling, lots of new manufacturers, new kits that would of never seen the light of day. It's a great time to get back in the hobby!
As far as primer/paint, I'm liking Vallejo's new rattle can paints.
They come in the major armor colors like Panzer Grey, US Olive Drab and probably 8-10 more colors.
Good Luck on your first project back !

you don't have to be great, just have fun!

Welcome back to the hobby! As said, a grey undercoat works fine, it'll bring to light errors and imperfections and is a good base for nearly every colour. Of course for other people other things work just as well, matter of taste.

Personally I prefer tamiya's primer. I tried some Vallejo cans, I'm not too fond. Again, matter of taste. They do smell better :-)

CMOT thanks for the welcome and the advice. I did some looking and I want to try Army Painter Primer/ Paint Desert Yellow.

ivanhoe6 thank you for the welcome and the advice. I did some looking and I want to try Army Painter Primer/ Paint Desert Yellow and Vallejo Spray Desert Sand.

southpier I am hoping to just be good I think with so many weathering product options and great tutorials on the net I can do it.

Florre my nephew has used Army Painter Primer/ Paints with success so I am going to try it with Desert Yellow.

I can recommend Tamiya Fine Primer in a rattlecan. Adheres well and is quite smooth. It dries farely quick. Just spray outdoors because of the oder. 70 degrees ferenheight is where it works best.

no question about it.

one suggestion: designate one of your less favorable models as a "paint-mule". use it to try out different techniques rather than on a model you have spent months getting to a point where a disappointing move would be disastrous.