How can I draw sugar with a pencil to get a realistic look?
I tried it like this (it's not ready yet):
Is it better to use stripes/dots or is there a better way?
We can assume that sugar crystals are cubes with different reflections inside. So, the overall task is to create some cubes and place gradients inside.
I did it in 5 minutes, so your results should be much more better than these:
I multiplied one cube with gradients as you can see. Of course, here the crystals look very large - for the sake of explanation.
If you try it by hand you probably need a hundred of different cubes.
My advice - take your smartphone and and take a photo of real sugar and explore it with magnification: you will notice the reflections, the shine and other features - try to copy some of them with pencil and little by little you will know the "sugar laws". This is the best way to learn.
ADD: As you can see sugar is white points on grey background and the very sugar structure one can feel looking on the margins of the powder. So you create a grey background and using an eraser/rubber create white points and some lines...
I agree that playing around with your phone and taking some pictures is a good way to start but I found that most the time you just need a couple little tricks, representations of what it is and the human mind will connect the dots, and see sugar as long as you give them enough hints at what you want them to see. You can be pretty vague and as long as there's enough reason to believe you're looking at sugar you will see sugar.
Also, the stem in your drawing wouldn't allow you to pour sugar very well from that container.