Because the book is quite big I can do several patterns on one page and so use variations of a certain colour combination and see how they look together. It also leads to very attractive pages, at least to me. :-)
For now I basically use Stabilo felt tip pens and choose four colours to play with. But I can see how in the future I will use different pens or coloured pencils and more challenging numbers of colours.
In any case it's a lot of fun to do these and see how many variations I can come up with.
Wishing you all a wonderful and artsy day!