You will need to strip off the old pain, then sand and clean the wood. IF you want to paint it, do so, if not, stain the wood, stain again if not dark enough, then you'll need to apply one or more coats of a clear, high-quality varnish to shine and protect.
Use an electric sander and sand the faces of the cabinets. When they are smooth you can go ahead and use a stain of your choice to color the fronts again.
first use a stripper to remove the old finis, appyied with a brush and removed with a scrapper, have to apply more than once, than the surface must be sanded
Anyone is able to refinish oak cabinets if they are willing to take the time. Make sure to cleran your cabinets well before proceeding. Spray down with household degreaser (ect 409)