What can you do to watch a child to make sure they don't attempt suicide again?

Constant supervision: It's most important to insure the child is in a safe environment - whether at home or in a treatment facility. The parent/guardian needs to be able to provide constant supervision and monitoring. The environment itself needs to be safe: lack of access to weapons, medications (even over-the-counter ones), sharp objects. Ongoing treatment is also crucial to symptom improvement.

It takes balance: Fortunately, strong suicidal feelings rarely last very long, especially in teenagers. But, someone who has made a suicide attempt before is more likely to do so again. If at all possible, partner with the part of the adolescent that wants to stay alive--if there weren't some part that did, he or she would be dead. Have them help think about would will keep them safe if the urge returns.