How do you improve your immune system mine is so weak?

Healthy Living: Don’t smoke, eat healthy (fruits, vegetables, whole grains, low in saturated fat), exercise regularly, maintain a healthy weight, control your blood pressure, drink alcohol in moderation, get adequate sleep, and practice good hygiene (washing hands frequently and cooking meats thoroughly). Make sure to have regular check-ups with doctor and try to reduce stress, this can wreak havoc on immunity.