Bert, besides being 100% sure of your target, there is one other way to avoid killing button bucks. Never feel pressured to kill a deer even if it is the last five minutes of the last day of the season. I've seen many people (including myself as a youngster) kill button bucks when they were trying to fill their tag during "crunch time".
When hunters take their time, get a good look at the deer they're shooting at, and are selective, the end result is almost always a good one.