How to paint wood?

Im going to paint the box of my subwoofers, and i dont know how to start. the box is going to be painted with automotive paint, the same color of my truck.How to paint wood?
the only way i've ever found that works is after it's sanded as smooth as possible, start applying coat after coat of a good urethane primer until the wood is no longer soaking it up. be sure to let each coat ';flash'; (lose it's wet look) before adding the next one. when it's no longer soaking it up, add 2 more coats so you'll have enough to sand later without going to deep.How to paint wood?
Remove the subwoofer system from the box. Fine sand the boy surface. Use a wood cleaner after you had finished fine sanding to remove dust particles and any other residues that may be on the box. Use a light or dark color primer depending on the color your truck paint is. It may take several coats of primer and paint to effectively do the job. You can apply several coats of clear sealer on it if need be.