Make your Model frame wider so that the frame contents fit better within the frame boundaries. You can do this by clicking once on the Timeline frame so that the selection handles appear, then click and hold down your mouse arrow on one of the selection handles and drag.
If you are working with the Timeline Model, you can also try the following solution. Select the Timeline by clicking on it. Choose Timeline Scale... from the Timeline menu. You will see a dialog box where you can change the timeline scale to a larger division. For instance, change the timeline scale from weeks to years. Because a larger scale has fewer data points, you may find that individual data points do not overlap.