Respect their independence. Be mindful of the balance between staying connected and “meddling." You can continue to be involved in a young adult's life, but give them space and freedom to start building their independence.
Let them learn. As tempting as coming to the rescue might be, this is a time for kids to learn how to solve problems on their own. You can provide emotional support if they come upon a crisis, but focus on stressing the importance of making responsible decisions as the best way to keep the same problem from happening again, especially if the problem involves use of alcohol or drugs.
Give them space and freedom to start building their independence.