I especially like the hint about cutting out extra trim to give the flat prints depth.
Something else you can do: spray-adhere your prints to foamcore (the 1/4" stuff, not the big heavy insulation...although there are places you could use that, too) and, when you have siding or other indented spots, use a straightedge and a fine steel crochet hook to press down the lines. A dried-up ballpoint pen will also sort of work, but a #5 or 7 steel hook has a smaller head and is angled. An unused #0 knitting needle with also work. Both are also handy when you need to score fold lines on the back of a print.
By the way, if you do those little glitter houses on the site (and you should if you like a traditional holiday toy look)...don't forget to let them dry well, then shake them and hit them with AquaNet hairspray before you get them near your year-round layout or the Christmas tree. Just don't ask how I found out that was important.
Thanks for the tips