Sketch?. .lets see. . .I use contour lines mostly. .especially on hands. .following the basics on hand anatomy makes it look awkward. .I also think that I have graduated from using boxes and circles. .coz Ive got the hang of doing human anatomy. .but i still use the sausage body. .(you know. .the ovals. .) whenever I'm doing complex poses. .like birds eye view. .or super foreshortening. .I sketch the bare body first. then add the clothing and the details. .before. .most of my works are sketches turned final drawing. .but now i use a separate paper for the final sketch. .I"ll trace the final lines of my sketch to the new paper. .thus cleaning my work. .and that's it. .^^
It depends on the medium. If it's pencil, I scribble and scribble, then I make a dark outline, sometimes, but mostly I go over it with pen after that.
I don't know how many sketch out there I haven't tried before,
But I tried stick man style, and block style guide lines, and some other type of guide lines before.
when it comes to sketching I just draw to make their basic shapes, you don't have to make them too awesome cause it's in sketch form.
if the main lines becomes not what I want it to look like, I fade them and consider them a sketch as well XD.