If you pick a restaurant where locals dine you can't go wrong, right? WRONG!! You're in Holland now, not in Italy. And we Dutch go to ANY length trying to save a buck. So if you want to avoid the risk of nasty suprises (e.g. salads with rotten ingredients) avoid places like 'Malle Jan', 'LA Bota' and 'Charcoal'. If you're on Budget, try for instance 'Anak Bandung' - an Indonesian restaurant, located near the Garenmarkt. If you're not on budget, try 'La Cloche', 'Burgerzaken', 'Het Prentenkabinet' or 'de Avonden'.
Leiden´s inner city is the second largest in the country. If you want to see it all, you really need a bike!
An obvious one maybe: don t forget! the water is wet :-).