Though e mails, Snapshot and Instagram have certainly taken over the old habit of postcard writing, many people still love getting a paper postcard delivered the traditional way to their mail box. Nowadays there are new applications for your phone like Postcard on the Run, that transform your pics into a postcard and deliver it to the post of the recipient you choose.
In your travel project, you will have to include a postcard. Writing a virtual or traditional postcard follows certain conventions.
Here follows a good interactive model of postal writing from the British Council. Do the on line exercises complete the downloadable worksheets you will find at the bottom of the page.