Begin by creating a simple circle using the Ellipse Tool (L). Give the circle a white fill and a 1pt black stroke. If you want more realism, you can measure the diameter poker chip and then click on the artboard. This will bring up the Ellipse dialog box, enter those dimensions in the Height and Width fields and hit OK.
The poker chip has an inner ring that is indented. To create this inner ring, use the Ellipse Tool (L) to draw two smaller circles, within the circle you just created.
Hint: Turn on Smart Guides (Command + U) and place you cursor in the exact center of the first circle you drew. With Smart Guides enabled, the cursor will snap to the center of the circle. Click the mouse button and drag while holding the Option key. This will create a proportioned circle from the center point, outward.
