sequence in painting ?

Insufficient data.

What are you painting? What effect are you trying to achieve? What kind/brand of paint? Do you have an airbrush? Are you using brushes or an aerosol can?

Point to a picture of where you want to go with your painting and you'll get a more specific answer.

Okay, that's better!

Prime the model. Apply multilpe light coats of the body color, lightly sanding with extra fine, no less than 1000 grit, sand paper between coats. Each coat should have more thinner in the mix. Pick up some polishing pads at the LHS for the final coat. While you're there, pick up some carnuba way and apply it like you would on a real car, buffing after it dries. You may want to seal the decals and apply a caot of clear gloss over them before the wax.