Here are several ways you can improve your immune system and help it function optimally:

1. Eat a healthy diet: Foods that are high in vitamins and minerals, such as vitamin C, vitamin D, and zinc, may also be particularly beneficial for the immune system.
2. Exercise regularly: Regular physical activity can help flush bacteria out of your lungs and airways, which can reduce your chances of getting sick. Exercise has also been shown to enhance the function of immune cells.
3. Get enough sleep: Sleep is important for overall health and can help support the immune system. Aim for at least 7-9 hours of sleep each night.
4. Manage stress: Chronic stress can suppress the immune system, so it's important to find ways to manage stress, such as through exercise, meditation, or therapy.
5. Avoid smoking and limit alcohol consumption: Smoking and excessive alcohol consumption can damage the immune system, so it's important to avoid these habits or limit your consumption.
6. Get vaccinated: Vaccines can help protect you against certain diseases by priming the immune system to recognize and fight the pathogens that cause these diseases.
7. Maintain good hygiene: Simple hygiene practices, such as washing your hands frequently and covering your mouth when you cough or sneeze, can help reduce your chances of getting sick and spreading infections to others.

It's also important to remember that the immune system is a complex and dynamic system that can be influenced by various factors, including age, genetics, and overall health. To maintain a healthy immune system, it's important to adopt a healthy lifestyle and seek medical attention if you experience any symptoms of illness.