Display development is a process. If you truly want to make an effective display, take your time. Do not expect the process to be accomplished in a week. Give yourself ample time to put it all together.
Design your display concept around one big idea and place only supporting elements for that idea into your display. Keep things simple and clear so your guest does not get overwhelmed with too many things to look at or to read.
By keeping things simple, you are not dumbing down to your guests, you are creating a conceptualization that is intended to have your guests want to know more. Displays are intended to educate, but they are also intended to inspire further exploration. In the exchange of knowledge in a display case, you cannot present every detail of a subject, but you can open the mind to questions that inspire.
Artifacts do not have to be 3-D objects, but to have two or three larger 3-D physical objects will draw greater interest to bring your guest closer to the display. These can be printed copies of original documents that may be too delicate to use for display purposes. Along with larger objects a couple of smaller objects related to the larger primary attention getters can help to fill out your display.
Plan around a central idea and use a few things to inspire. Consider your guest first in your planning and how they will be affected by your display. Keep your display simple and well balanced. Inspire your guest and leave them wanting more!