Laminate cabinets were all the rage in the 80s. They were cheap and durable, but now it seems like every outdated kitchen has these knocking your reno budget out of the park.
A high quality brush is a must. This will help you get a smoother finish. You should do multiple thin layers instead of one thick layer to avoid drips.
Use the paint brush then a roller to smooth, and sand between coats. Caulking the seams will help make the door look more polished. You can add a protective sealant coat to protect the paint.