Keep out of direct sunlight and of course, out of extreme heat, cold or high humidity areas.
An item should be able to removed from the display and be in perfect condition. For some examples and ideas for displaying, take a look at Screen Used web site.
The company has done everything from a display for matchbooks from Back to the Future to a custom mannequin for an actual Superman costume, complete with facial mask to look just like the character from the movie.
The biggest drawback with these custom displays is the shipping. Many times it's just not very cost effective to make a large display piece and then ship it across the ocean, etc.
One of their biggest challenges was making a display for a Harry Potter wand, one that allowed it to be removed from the case without any problems.
Note: Image is an example of ScreenUsed.com's detailed display cases. These are the holsters and guns used by Angelina Jolie in Lara Croft: Tomb Raider. Values would be approximately $10,000.
