Both mint - stamps (unused stamps) and used stamps can be collected. These can be collected year-wise , nation-wise or theme-wise. To make this easier and more attractive to beginners, philatelists generally advise you to collect stamps according to a selection of your choice called a Thematic Collection. Themes may be flowers, birds, animals, architecture, railways, monuments, Red Cross etc... Definitive stamps and stationery can also be collected as a theme. The bottom line is that the collection unfolds various aspects of a theme like a story.