You can do this by logging in and clicking the 'Promote now' button in your profile, exhibition, or artwork settings screen.
You can be featured for a whole week for just 7,90 € - If you still have 'credits' left you can highlight your work by clicking on the button.
Otherwise you can go to your payment settings and buy a promotion credit via PayPal or Credit Card (You don't need a Paypal account).
This means that your location or show will be illuminated red on the map like the Glarify logo, and you'll be represented in the promoted rank for one week. It's cheaper than printing flyers and a much better way of attracting art fans who use Glarify.