Be positive - Assume you will not have problems. Do not go looking for problems or making issues. The majority of colleagues will not want to make life difficult for you but will be supportive and friendly. Keep a sense of humour - Do not assume that everything said is aimed personally at you. It is important to keep a sense of perspective on all issues.
Aggression is hostile, blaming and demanding.
Lack of assertion can be due to fear of displeasing others and not being liked. However you need to learn when to shout out and be heard and when to say no. 6. Along with assertiveness also be pleasant and smile. Its fine to have a door opened for you to walk through or a seat offered in a crowded room. It is not singling you out as weak but just good manners being practiced.