This is a very important topic and I dont remember being it discussed before. So here it goes.
Simple tips from top of my head.
>Always clean your hands before eating by soap or alcohol sanitizer.
There is another technique- barrier substrate such as KISSCARE polymer. Basically it doesnt allow dirt, oils and microbes to bond to your skin. So hands can be easily washed with just water.
>Keep your nails trim so that they can cleaned easily.
I have read some people cut nails with scissors. If you want a nail cutter best solution is Wenger clipper.
>Stress, inadequate rest, and too much exercise will actually run down your immune system and make you more susceptible to illness.
>Avoid junk food, most of which are inflammatory. Better then to rely on Ibuprofen.
A diet low in red meat and high in fish, fruits, nuts, cereals, mushroom and vegetables is good. Green tea is considered good too and so is dark chocolate.
Any more tips??
I will put all the info in wiki when I get time.