To enhance your foyer, try painting it with a color the with complement and unify the decor of the home. Or if its visual interest that you lack, try a wallpaper (murals, geometric, and toile papers are very cool). Crown moldings also make a huge impact, and whatever upgrades you make will not be to expensive, because it is such a small space..
What if you don't have a separate foyer....if you have a front door you can certainly create one. This can be achieved by using area rugs to define and anchor the space. Also a antique table with a small arrangement of seasonal abjects ( love cinnamon scented pine cones). Mirrors and paintings also add dimension and definition to a space. Don't forget to add well appointed lighting., this creates a Just keep in mind add space and not a place to collect clutter.