There are many homes out there that have either a very small yard or no yard at all. You will need to figure out how to create some curb appeal if you want to sell it.
If you have a small yard you can landscape it by creating areas of plants and flowers that attract the eye to the home.
For the home with no yard you can create an attractive yard effect by using the area around the porch or on it.
My personal ideas for the porch aspect would also include a trellis with potted vines or climbing flowers. Doing this would still give you the desired look but also give you that close to nature feel that you want when you go out there to relax.