There are budget and printing considerations you should determine before beginning any design, as those considerations will define certain constraints of the design.
You should know in advance how the documents will be produced. Are you going to print them directly to your desktop printer or send them out for traditional offset printing? The key consideration here will be your use of color.
4-color process (required for color photos) or multi-color designs can be very expensive to print either way ink cartridges for your desktop printer are expensive, as is color offset printing.
If your budget is restrictive, and who's isn't, you might consider using only grayscale images and shades of gray for design elements. Or you might choose one additional color (in addition to black) to use for highlights resulting in a 2-color "spot" print job.
Since our flyer project resides in the world of book fantasy, we get to work in full color! Enjoy it, it might be your last time.