You may like to try this method of seeing/drawing if you have not tried it before.
Set up your table so that the thing you want to draw is at one side of you, and your paper is well to the other side so that you cannot actually see what you are drawing! Make sure your paper is not going to slide around and place your pencil or pen near the middle of the page. Now look only at your holly leaf (or whatever else you want to draw) and take your eye around the edge of it very slowly, drawing your line at exaxtly the same very slow pace as your eye is moving. Your hand is recording exactly what your eye is seeing at the same time as you are seeing it. This will maybe feel very strange if you have not done it before!
You may make a false start or two, but once you get into it you will probably become fascinated at the inticacy of the shapes and your left brain (the wordy part) will quieten right down and you will make the shift into right brain..an almost meditative state although you will be concentrating fully on the experience of both seeing and recording. This is a wonderful 'warm up' exercise, rather in the way a pianist might play a few scales before practice.
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It produces preliminary sketches which are often very beautiful in themselves.
Read more about this method in This excellemt book.