I get asked this question all the time so I putting the information here once and for all :fingerscrossed:
In our 'template' gallery there are tutorials to help you and templates/bases to use to get you started.
Also this dA article on stamps and how to make them and use them can help you http://news.deviantart.com/article/148282
The rest of it is trial and error on your own, good luck :)