What I find best, is try using a cleanser on your face first. it will remove oil and dirt, then apply sun block. Oil of Olay isn't very good if you're going swimming, or doing a sport. it's great for everyday wear. But, if you have oily skin, it does clog your pores. The brand of sun block doesn't matter, as long as the SPF is over 15.
I hope I helped you out!