Keep Your Word: A healthy relationship is based on trust. Always keep your promises. If you have told her that you would do something for her then do not back off. Keeping your words is very important for building up a strong relationship in future. Do not make promises unless you are sure that you can keep it. If you fail to do so then she would lose her trust in you.

Respect your girl: You should not criticize your girl, belittle her or be rude to her. You should not become too nosy or too interfering. Remember she has the right to live her life her own way without someone watching her every move.

Do not dwell in the past: It is important to leave your past behind. If you always keep talking about your past relationships with your new girlfriend then chances are that initially she would feel sympathetic but later on she would get bugged listening to the same old stuffs.

Stop being possessive about her: if you keep track of all her activities when she is not with you, then get rid of that habit. Caring for your girlfriend is different from being overtly possessive. If you do not give up your habit of demanding explanation for every single thing which she does then eventually your relationship would become unhealthy.

Accept her for who she is: Love her for who she is and do not try to change her. Let her be herself. Do not complain about her looks, her extra kilos, her hair, her skin etc.

Pay attention to her: being a good boyfriend also means being a good listener. When she gives you a hint about something she likes then pay attention. Pay heed to her needs. Listen to her problems and give suggestions to solve them. Please make it a point to remember her birthday at least.