What is the best way to paint paneling?

If paneling slick rough up with sanding. Then apply primer. Then paint. Lasts forever.

If paneling is slick, wash with TSP, no need to sand.

Use a good primer, than paint ..that simple!, that's all I did and it looks good and has held the paint for over ten years

I agree with Nancy! Make sure the paneling is clean and dry. Prime with a good stain blocking primer like Zinsser 123 or BIN. Then paint like regular wall painting. If the paneling has grooves you can fill them with drywall patching compound. Let it dry overnight. Next day use a damp sponge to smooth the patch. The prime and paint.

Primer and paint worked just fine for me.

We painted wood paneling to make it much lighter in the living room and hall. You might want to lightly sanded the paneling prior to painting. The finished look is wonderful. Our paint color is white.