Some of us have made bad first impressions in front of people we wanted to become good friends with. First impressions are important because they form the foundation from which all future thoughts about someone will be based. Therefore, making a bad first impression may be difficult to erase from someone's mind. However, there are actions you can take to change people's bad impression of you.
Apologise immediately. A sincere apology can go a long way because you will prove to everyone that you value their thoughts about you. Tell the people you offended that you didn't intend to offend them and that you wish to rectify the situation. Explain the reasons you acted the way you did in your apology. Be careful not to over-apologise because it will make others feel uncomfortable that you keep bringing up the past.
Use humour. When you are around the people you made a bad impression in front of, poke a little fun at yourself. Once they know you are not afraid to laugh at yourself, it can break up some of the tension. Remember to only direct humour at yourself to avoid any more feelings of discomfort.
Do not make assumptions. After you have made a bad impression, it can be easy to assume that everyone thinks the worst of you. However, things aren't always as bad as they seem. Instead of assuming what someone thinks about you, explain to her that you feel ashamed about how you acted and ask her how your behaviour affected her.
Pay attention to future behaviour. In order to overcome a bad first impression, future behaviour must be consistently good. With enough time and patience, gaining trust and changing perceptions is possible.