As for how to preserve leaves for a display to show, some suggestions:
1. There are various methods but as for rules to follow for any type you choose:
A. Pick leaves that are overall flat and not curled
B. No spots or bumps and are overall smooth
C. Various shapes and colors work well and offer a good variance
D. Look for leaves that are dry and not too much moisture.
2. As for methods to preserve:
A. Two methods listed here as one uses Glycerin and the other uses wax paper
B. ***** ***** offers a video on how to preserve and place in a frame
Good luck with any of these methods as you should have a display to show for guests as well as yourself to enjoy. I hope that these suggestions are found helpful as please let me know of any additional questions/concerns you might have. Also if you could take a second to rate my assistance so that I know my help was found useful tonight.