to get a good piece written you only have to rewrite a draft and to get a good draft written you have to turn a series of notes into a continuous text and as a series of notes is just the argument of notes you already have in your zettelkasten all you have to do is to have a pen and paper in your hand when you read to collect ideas and write them in your own context.
a good way of understanding what you read is to translate it into your own understanding into your own context and then save it in your zettelkasten this will transform what you consume into something totally new and your own and as a result, your zettelkasten becomes richer your own thinking as well become richer