Several Avery labels are 20 per sheet, 1-1/2 inches round. You can design these using the 8293 template in Avery Design & Print Online.
You can also use a template built into Microsoft Word or download an Avery 8293 template for Word, Photoshop, Illustrator, InDesign or Pages.
Here's some information on recommended printer settings.
If you want more information about a specific Avery label, search for the product number on avery.com.