When I was doing cars I would go to the library and photocopy pages from the repair manuals for different engines for firing orders. I put these into a folder, along with other articles I thought that would come in handy. Now that I do mainly diorama buildings it depends on how detailed I want to do the interior of a building. Most dont come with any interior, just the basic bilding outside, so depends, on how much I want to go. For instance here is the building I started with. %5BIMG%5Dhttp://i8.photobucket.com/albums/a2/mercman51/HO buildings/Goodfellows Hall/Goodfellows.jpg And the interior I made for it. Most everything inside is scratch built. <a href="http://s8.photobucket.com/user/mercman51/media/HO%20buildings/Lous%20Drunken%20Leprechan/Bar015-1.jpg.html" target="_blank"><img src="http://i8.photobucket.com/albums/a2/mercman51/HO%20buildings/Lous%20Drunken%20Leprechan/Bar015-1.jpg" border="0" alt=" photo Bar015-1.jpg"/></a> I did a Google search for some of the items, others like the pool table, and dart board I measured the real item, and scaled them down.