Create open communication lines. It is never too late to ask your child open-ended questions about trust. Let them define trust and how it can be broken. Teenagers are smart. You will be surprised to hear how mature their answers could be. In the case of broken trust in the family, have an open discussion on how it can be regained and how the family can be reunited. Reiterate the fact that trust is a two-way process which requires efforts from both ends.
Explain the benefits of trust. Trust is beneficial to all members of the family. The family environment becomes peaceful when every family member is trusted by each other. No arguments will arise. Teenage kids can enjoy weekdays without curfew if their parents trust them - that they won't do anything that will ruin their lives. Parents, on the other hand, will be free of worries. They will also be able to focus on their work because they feel confident that their teenagers are safe and sound wherever they may be.
Create a road map for success. Telling teenagers to “do the right thing” will make it difficult for them to understand how you want them to act in order for them to gain your trust. Give them specific goals and NOT instructions. Instructions tend to make teenagers rebellious. Give her a list of things she needs to do in order to change bad behavior and habits. Instead of starting these items with "Do not", start them with "I will".
Believe that you're a good parent and trust yourself. As a parent, you know what's best and right for your children. Set goals for yourself too. Make sure that these goals are targeted towards your transformation into a trustworthy parent. Make also that these goals are reasonable and achievable. Be patient and understand that trust grows slowly provided that good decisions are made.