A lack of assertiveness must be differentiated from shyness and timidity, both of which are character traits. A lack of assertiveness is sociologically unacceptable, leading to difficulties with social or professional life.
Self-help is difficult and a consultation with a psychologist is most beneficial to differentiate between acceptable and unacceptable levels of poor assertiveness.
Homeopathic remedies can have a profound effect on areas of psychology and special interest should be paid to the remedies Baryta carbonica, Pulsatilla, Gelsemium and Petroleum.
Martial arts training is excellent at increasing assertiveness, especially Qi Gong.