How do you keep your tan after summer?

Summer is almost finished.... And I really want to keep my tan as long as possible... Does any of you have tips on how to keep a tan after summer?

Also, I'd like to know what's your favourite way of getting a tan throughout the year (sunbeds, fake tan at home, spray tan in a salon...). I know there are many options but can't decide which one is the best.... Any suggestions??

Jane Xx