What is the best way to paint light switches and plates?

I have already tried to "just paint it" and it gets all gummy and sticks to which every position you paint it in,I have left it in the same position for days and it still did the same thing. I have painted and then removed and then repainted four times now, and still the same or it runs and one side it thicker. I am so frustrated my walls came out beautiful, but...... please only answer if you know what your taking about, thank you