Contouring round face

I have a round, bun-like face. Please teach me some contouring techniques. It doesn't seem to work very well for me; my face still looks bulky with a lot of empty space, haha. Also, since I have oily skin, it seems to wear off quickly. Please recommend a product that doesn't fade even on oily skin, has good staying power, and lasts a long time. Something easy to use, too.