Chart, compass, water, food, extra clothing, tools and spares, extra line for the anchor and sun protection are some of the items to think about. Unless you have an electronic system such as a radar or GPS, do not go out of sight from the land. Remember the wind blows harder over the sea. Land winds are only about two thirds the strength of sea winds. Small craft of runabout size and less should not generally venture out of sight of land.
Most boating accidents are the result of a series of smaller things going wrong.
The more things that you get right, the less likely you are to hit big trouble. The time to start getting them right is before you set out. Plan for even the smallest trip.