Play up the eyes

What does 'play up the eyes' mean?

And what does the last sentence mean?

Jess was torn between two - one a long, strapless, basic black number, the other a knee-length electric blue with spaghetti straps. I encouraged her to go with the blue; why not play up the eyes? Angela chose a pale pink dress that draped around her tall frame nicely and brought out honey tints in her light brown hair. I complimented them both generously and helped by returning the rejects to their racks. The whole process was much shorter and easier than similar trips I'd taken with Renée at home. I guess there was something to be said for limited choices.