When the second coat of primer is dry, paint over it with a couple of coats of latex satin or semi-gloss enamel, allowing each coat to dry before painting another.
After the finish coat is dry, seal it with a couple of coats of clear acrylic. Use satin or semi-gloss sealer to make the seal stronger. Avoid egg shell or flat paint.
If the counter does not turn out how you expected, lightly sand the finish, add another coat of primer and repaint.
This process can also be repeated every few months to keep up with current color trends.