30. Never Swim Past Your Abilities
Children, in particular, especially those who are able to swim, may decide that they are better at swimming than they actually are. They may choose to dive into the deep end of the pool when they are not able to.
Swimming past your abilities, trying to do things in the water that you actually do not have the skills to do, is one cause of drowning. If you want to gain better abilities for swimming, the best thing to do is take swim lessons, not push your own limits.