It is tempting to fill every corner of a piece of stationery, especially when there are more ideas waiting to go on the page. I prefer to pause before adding one more detail. Paper goods need room for their own purpose: a written note, a useful label or simply a small image worth looking at.
Leave space for a message
On a card, the person writing should not have to squeeze their words around the decoration. Keeping one clear area open makes the design more useful without making it plain. A small illustration near an edge can give the page character while leaving the centre ready for handwriting.
Give each detail a reason
A border, motif or extra colour should help guide the eye, not simply occupy space. I like to check whether a detail supports the main idea or pulls attention away from it. If it does the latter, taking it out can make the whole design feel more complete.
Make texture part of the choice
Paper has a presence before anything is printed or drawn on it: its surface, weight and how it sits beneath a pen all affect the experience. When choosing paper goods, consider what you want to do with them as well as how they look. A design with breathing room gives those material qualities a chance to come through.