So this is how I start a character piece.
1 - rough sketch of figure making sure proportions are all correct.
2-rough out design, clothes, accessories etc...
3-get reference. Some artists usually do this before they start drawing but i found that my drawing would be influenced by the reference rather then my design influence what reference I get. I am only now starting to use reference and my work has taking a huge leap forward in looking a lot better
4- Detail line art of character and designs.
5 - close up showing how I use line weight (different thicknesses of lines to make the line drawing more interesting. Line art changed my sketching forever. I Can't even tell you how terrible my sketches looked before I knew about it.
I always give myself a little story to help ground my design decision so this Joker is from a post-apocalyptic future where resources are scarce and you need to make do with everything that you find...
A simple story like this will explain why he is wearing different knee pads and why his clothes are so tattered... In the rendering I will push this idea further
Hope this helps.
Part 2 will be the colouring of this image.
Will post that sometime next week