You can design your small garden design as complicated, or as simple as you want. If you are really into following directions, buy some landscape design books and immerse yourself in all the details. I am sure that you will rethink your idea to get involved before you are half way through the first book.
Designing your garden to be beautiful not only to spring and summer but also in the winter months in the key to a successful all year round garden. People love to use their garden and become outdoors as much as possible, so it is sensible to design your garden for all year round use.