This article shows you several ways to enlarge and shrink artwork in Adobe Illustrator.
Steps

Step 1. Select the Zoom tool
The pointer becomes a magnifying glass with a plus sign in the center.

Step 2. Click in the center of the area you want to enlarge

Step 3. While holding Alt, click in the center of the area you want to shrink

Step 4. Select View> Zoom In (or View)> Zoom Out
