It might look the same as the last two on the small screen, but this one is different: it’s twice size and twice as complex which meant it was twice as easy to get lost! (Also twice as easy to get frustrated or bored, give up and go do something else.)
Painting drapery is about carefully managing the values and not getting lost with the drawing. If necessary use a grid! You can make one with cardboard and string then suspend it in front of the subject with whatever artistic ingenuity is required to get the job done. You will quickly find that it’s necessary to keep your head in the same position as you draw. (Don’t worry, it does get easier with practice.)
Don’t draw too much, drapery might look complex but it does follow thae same pattern as any other painting. Indicate the largest shapes – like the main roads on a map – which should then be enough to figure out where the streets are when you get to them. If you draw too much detail it is tempting to try to paint inside the lines rather than paint the big shapes and add the smaller ones over the top. (That’s pretty much the difference between painting and ‘painting by numbers’.)
Rough in the darkest dark first because this will set a marker for the value range. Decide how light the lighest lights can go and the rest has to fit in between. With the range set it’s a matter of deciding on the dividing line between light and shade. The rest is puzzle pieces – fit them together and then add a few details to finish.