There are plenty of things you can do to keep your immune system strong so that you can avoid winter colds and flus.
1. Eat nutritious food. Okay so this doesn't only apply for winter, but if your are going to potentially be faced with more bacteria and viruses in winter then making sure your are ingesting as many nutrients as possible will help your body keep up with the requirements for strong defense.
Sleep is essential for health and vitality all year round but as I've mentioned winter is a great time to get more sleep, so why not use the cool winter nights to work on improving your sleep quality and quantity.
Sleep debt/deficit (the difference between the amount of sleep you should be getting and what you are actually getting) is fast becoming a major health problem. More and more people are getting less sleep than is recommended for well being, which is 8 hours per night for the average person.
Write something about yourself. No need to be fancy, just an overview.