The medical causes needs to be ruled out like low blood sugar, hyperthyroid state, cardiac abnormality etc. You should quit
coffee, smoking, tea, alcohol, heavy meal which can trigger blood pressure and cardiac load leading to palpitations. Get an ECG to rule out any heart condition, blood sugar, thyroid status. If any medical condition found, should be treated accordingly. Relaxation exercises, listening to music, bathing with warm water, massaging with oil etc will help you.