Dull knives can easily be sharpened by using abrasive utensils like a ceramic sharpener or one coated with industrial diamonds.
Unlike the honing steel the diamond / ceramic sharpener can actually reshape and restore the edge to its original factory geometry.
Hold the steel with your left and the knife with your right hand (lefties simply do the opposite) and guide the blade with light pressure across the steel. Do this in an arching motion, side-to-side, at a 20o angle between blade and steel. Repeat this process 6 - 8 times. Never stroke each side more than once in succession.