Postcards. Bought for friends, relatives, colleagues and pets alike. Sometimes they are even bought and not given to anyone but rather taken home just to look pretty. A postcard is a mood, a thought, a quote; a memento of a moment in time.
An A5 rectangle is not a lot of space for a quality, eye-catching time memento. Simple, clean lines and clear, short copy is a good way to get the most of what little is available. Use of colour is an important consideration too as this will almost certainly be the dominant influence on the mood of the card. The best pieces stick to a colour palette or use colour to selectively draw attention to specific subjects.