The cupboards should be well cleaned of all oil, dirt, grease. I use TSP for that. Other people use a paint thinnner or (bleach watered down). Sanding lightly would probably be good. (Take the shine off the paint if there is one.) After that run over with a tack cloth or damp rag to remove sanding dust. I used melamine paint for my cupboards. It is strong smelling/fuming and reqiures lots of ventilation. It is very durable and easy to wipe clean. Read the can to see if a primer is required. Go to your local paint store and ask questions there as well.