As Lisbeth suggested, tattooing is probably the only real way to make them appear larger.*OUCH*
If you're just interested in larger areoles as a matter of personal taste, that's fine and by all means do what you can to achieve the look you want.
But if it is some kind of feeling of inadequacy, know that small areoles are normal in natal females.
As a genetic female, both my nipples and areoles are small, in fact my areoles are translucent and barely visible. I've seen men with larger, more obvious areoles than mine.