Use the correct type of clear coat finish. For most furniture paint projects, use Polycrylic as your top coat. It will give you the durable finish you're looking for, but won't yellow over time like Polyurethane will. Also, Polycrylic cleans up with water. You'll have to use mineral spirits for Polyurethane.
Faux wood garage door. I just did our garage door this spring. Only $40 for a quart of mustard-yellow paint and 2 quarts gel stain (2 different colors) . Sealed with polyurethane so it would gradually patina/golden over time. Looks amazing!! Beats a couple thousand for a real wood door.
I painted over it using Annie Sloan’s ‘Napoleonic Blue’ Chalk Paint then added two coats coat of clear water-based satin Varathane on top. It’s for an active boy so I wanted to reinforce the paint with extra protection!
Water based topcoats for painted furniture. When your paint has dried for at least 24 hours, apply a water based polyurethane to protect your surface. Do not use an oil based polyurethane, it will amber or yellow over time.