The raised bed

Raised beds are very useful to create in a garden and especially in a small garden - if you have never considered the benefits, perhaps these few points may convince you to try it out.

Firstly, by creating a raised bed, you have the opportunity of filling the area with really good soil and incorporating a lot of organic material into it - this is especially beneficial if your garden has poor, sandy soil or soil that is heavy clay.
The materials used to retain the raised bed can be anything that works for you - stones, bricks, poles etc.
The depth of the bed depends on the space available and the choice of plant material that you wish to put there.

For vegetables, a raised bed is really worth while as it allows you to have the ideal soil necessary for good growth and there is less chance of animals ( or children ) damaging the plants.
Fruit trees can also do well in a raised bed as you can fertilize them with ease and keep weeds and other plants away from them.

Maybe you would like to just have an attractive higher level in the garden with plants that have a cascading growth effect.
A raised bed alongside the lawn keeps the lawn grass out of flower or vegetable beds and gives a really nice neat appearance.
If you would like to have more height in your garden for privacy, a raised bed can be planted with shrubs and trees and will immediately give you this.