I'm certainly not the Graph Reading Expert that others are, but the ability to consistently limit on Sandies depends on the utilization of a Graph to make quick and proper decisions. If you have four hours to put 75 or 100 fish in the cooler for folks who normally don't fish, you need to cut down on the fishing time and increase the catching time. If you know the lake and season well, you limit the number of spots to fish. If you don't know the lake well yet, your mapping feature is invaluable. Look for Points, Humps, Roadbeds, Drop Offs, etc. and find the baitfish. Whites really relate to only one thing and that's bait (Shad usually)and they use structure to "herd" them and the buffet is on! A good Lowrance or Hummingbird Graph with Side Imaging and Downscan will pay dividends when the fish are hard to find, hugging the bottom or not feeding aggressively. In Cooler months, you may fish in an area where you only find a few "bumps" on the bottom. In Warmer months, your Graph may "light up" and as one of my Kiddo Customers once told me..."Mr. Simmons, there's so many fish that there's no room for the water"!
I find many folks tell me "The graph was covered with fish and they wouldn't bite". I believe these folks were looking at baitfish and not fish. If you find Sandies and the Graph is covered, you will catch fish if you're using the proper bait. (Normally Slabs, Slabs and more Slabs) A real key is finding fish holding to the bottom. They will be feeding. If suspended in large #'s , you're also in business.
If you're serious about learning how to find and catch White Bass, I'd recommend you inquire about a good Guide on the Lake you want to fish. I tell folks that in four hours, Adam or I can teach them more than they will learn in six months on their own. We're not that good, we've just been doing it six days a week for twenty years.
If you find a few Graph shots that look like those below, you're in business. Good Luck!