I am 26/f unmarried. I have been diagnosed for herpes simplex syndrome two times. What precautions I need to take so that it doesn't come any more?

Complicated. Herpes lives in your nerves forever once you first have it. You can reduce outbreaks by controlling stress and some medicaitons can prevent or lessen the severity of recurrances. Your concern should be what to do to prevent spreading it to others. Check the tips and other posts to educate yourself on how to control the disease.