Personally, I don’t feel quite old or weakened or frail enough to get a vaccination against the seasonal flu, and in general, I don’t believe in them unless for one reason or the other you are at risk in terms of complications such as pneumonia. This is up to each individual in consultation with their GP.
But I do believe there are things we can each do do limit the risk of catching colds and flus.
Apart from all the advice on nutrition, exercise, sleep, and fresh air (including airing out your house or flat at least once a day), the best way to prevent the seasonal colds and flus, in my experience, is to become SLIGHTLY obsessive about hand hygiene. Wash or disinfect your hands not only only after bathroom visits but also when you have, for example, been on public transport, touched door handles at work and in public buildings, and handled money, especially paper money. And of course before you cook and eat, and even before touching your mouth, nose and eyes. If ordinary hand soap dries out your hands, most hand-disinfecting products contain glycerine and are therefore not so hard on the hands.