Think about how people will see your design.
Designs too high might be hard to understand.
Keep it simple and clear, especially from a distance.
Use vector files (.EPS or .AI) for the best results.
If you can't do a .EPS or .AI the best option is a .PDF
Vector files can be resized without losing quality.
Bitmaps might pixelate when resized.
Some designers use a mix of vector and bitmap.
Create your design in the same dimensions you want the final print to be.
Resolution depends on size and viewing distance.
Use at least 150 dpi for close viewing (up to 10 feet).
Use at least 60 dpi for farther viewing.
All faculty and staff in RJUHSD have access to the full Adobe Creative Cloud Suite, including the premium version of Adobe Express which has lots of templates and resources for creating designs.
If you are familiar with Canva or other design software those are great resources as well.