Here is a pattern that is very useful as a border. How to draw the basic pattern is shown in steps 1-4 and then I’ve done some variations. In the first one the shading is done with a regular pencil. In the next two I used a liner pen with a finer tip to draw on the inside. The basic outlines I did with a Faber -Castell PITT artist pen Size S (which I think is roughly 0.5) and for the finer tangles on the inside – a 0.1 Uni Pin Fine Line.
Here is an idea how to make a Valentine Card zentangle style. It’s very easy, the patterns are simple, but it’s somewhat time consuming because of the small circle pattern, which I used to fill in the card. However doodling is also very relaxing and you can spend an afternoon chilling out while making some valentines.