You could try doing some Cognitive Behavioural Therapy with a professional or reading a book on that subject and trying it at home. Cognitive Behavioural Therapy has been demonstrated to be particularly effective in helping patients with problematic thoughts. Here's wikipedia's description of CBT: Cognitive Behavioral Therapy (CBT) is a psychotherapy based on modifying everyday thoughts and behaviors, with the aim of positively influencing emotions. The general approach developed out of behavior modification and Cognitive Therapy, and has become widely used to treat psychopathology, including mood disorders and anxiety disorders. The particular therapeutic techniques vary according to the particular kind of client or issue, but commonly include keeping a diary of significant events and associated feelings, thoughts and behaviors; questioning and testing assumptions or habits of thoughts that might be unhelpful and unrealistic; gradually facing activities which may have been avoided; and trying out new ways of behaving and reacting. Relaxation and distraction techniques are also commonly included. CBT is widely accepted as an evidence-based, cost-effective psychotherapy for many disorders. It is sometimes used with groups of people as well as individuals, and the techniques are also commonly adapted for self-help manuals and, increasingly, for self-help software packages.

Counseling.

You don't. Instead you develop equal self control and get better things to worry about.

Repeat after me "I'm not that important, I'm not that important. I'm not that important. (I only imagine that the world revolves around me)