I spent years in wool cycling shorts with real chamois. It was horrible. The chamois dries out and feels like cardboard covered with sandpaper. It takes alot of care to keep it supple and I can't remember what I did nor didn't do, but the result was terrible.

Like everybody else said: Cleanliness (but don't use antibacterial soaps and don't overwash), getting out of your shorts right away, and having a the right fit and right saddle are the most important. Also stay away from sugar (hard one for me, as I have a huge sweet tooth), drink lots of water, not just sports drinks, and of course general very good nutrition.