There is nothing wrong in being good to all. And attitude does not mean that one has to be rude to others. Also confidence needs to be seen as an understanding of the self. This includes understanding and accepting ones virtues, and limitations alike, and working with them. Assertiveness is when you are able to respect others thoughts, and rights and do not trample them, at the same time you do not let others do the same to you. Assertiveness is a skill that can be learnt, and sessions with a psychiatrist would help. Solution to problems are not tips to do stuff, one has to put an effort and work with ones own circumstances and reach the best solution. In psychiatry we don't tell what others have to do, we help them take their own decision as ultimately each person has to do the best according to his own self. To be confident, like yourself, and focus on your positives, and achieve things that you can, and give importance to family, and social network, and take care of yourself. Feeling good includes all parts of life, psychological, social, academic and physical. Talk to a psychiatrist in person, for more.