Practice swarming

Here is a link where Jeff Sutherland, one of the co-founders of Scrum, explain the why and what of swarming.

Even though he is prescribing this as a way to improve productivity, I think it will also help to identifyminimize the risk of a "failing sprint" earlier.

In a typical Scrum team, developers are assigned specific stories to work on. So, when the Sprint Planning is done, if there are 6 developers in the team, they start on one story each. In this method, when you look at the burn down chart, it takes what some people call a "deep dive" at the end of the sprint, even if all the stories are completed within the sprint. Meaning 6 stories could be open one day before the sprint ends and all 6 stories could get completed on the last day. This maximizes uncertainty. The Scrum Master cannot tell till the last moment whether many stories will be left incomplete.

Though you cannot eliminate the uncertainty completely, by doing swarming you will have fewer partially done stories towards the end of the sprint.