Cole Nussbaumer Knaflic has some alternatives to circling an item you want people to notice:
You’ve seen it before: a circle on a slide or graph that is meant to highlight something of note. People tend to be surprised when I express admiration towards this approach. I love that it means someone took the time to consider the data and the viewer and thought, “I’d like people to look here” or “I want to make sure my audience doesn’t miss this.” Then they took an action—adding the circle—to help ensure it.
That said, the circle is a blunt tool. It’s better than nothing: if you are facing such a time constraint that you don’t have a minute to spare for anything beyond quickly adding a circle, do it. If you do have more than a minute, however, there are other eloquent solutions you can employ. This will typically involve making changes to how you design the way the data or supporting elements are formatted.
Cole then lists out several alternatives. When I circle (or wrap with a rectangle), it’s usually one of two scenarios: either I’ve just grabbed a screenshot (or have frozen the screen in ZoomIt) and that’s my primary tool available, or I’m working with a pre-generated image and can’t change it. But when you have a chance to alter the base graph or image, Cole has several excellent techniques to make certain items stand out in contrast to others.