if you can still see them, then you're not putting enough on. Don't cake it on, but put on enough so that you can't see them. Concealer can also be used under foundation, so maybe a light coat of concealer and then apply your foundation. http://www.marykay.com/color/concealers/mksignatureconcealer/default.aspx
above is the link to show the shades I use.
below is a webpage where you can get application tips for applying makeup
http://www.marykay.com/whatsnew/tipstrends/default.aspx