Before traveling, it is a good idea spending some time researching the history, dates of the festivals and cultural events of the place that you are going to visit. This way, you enjoy your visit better and do not risk being taken by surprised by a holiday.
Get information about the working days and times of the places that your are going to visit. Check the possibility of having the services of a guide of from the visited institution, too. Most museums have an educational sector, and some of them offer didactic materials to support the visit.
Get information about the use of cameras and camcorders in the museum, church, or exhibition that you are going to visit. Many places do not accept the use of those pieces of equipment.
Avoid speaking in a loud voice, running around the rooms, or touching the exhibited objects in the museums. Many of those objects are fragile and may be damaged if having contact with hands.
Leave the places exactly as you found them. Do not collect fragments or move the objects from their places. In case there are professionals working in the place, such as archeologists or restorers, try not to disturb them.
In your trip, enjoy everything that the visited city/town has to offer: visit the buildings and areas landmarked as treasures, the monuments, the historical buildings, the museums, the theaters, the art centers and the concert halls. Discover new flavors trying the local gastronomy. And take part in the local cultural events, in the parties, enjoying its dances and music, thus contributing to the preservation of those activities.