well for me, i started with the 3-9 style and just tried to mimic the box art. i've always been pretty good at what i refer to as "sight drawing", which is mimicing a referance image, usually enlarging it. i used to redraw my pokemon card pictures on full sized pieces of paper that way. but i digress...
for years i was also a wolfy antro artist before i started doing cartoon/manga people, so once i started figureing out how the ponys worked, i just started doing the similar way i'd draw my wolves shape and "skeleton" wise. draw the head shapes, a guide line for where the back would go, then the leg guides. i'd also looked up other how-to tutorials and saw how others formed their basic body structure shapes and thar really helped to. and since then, it's just evolved more into my own drawing tricks, making it more my style that's loosely based on the mlp art.
now with te FiM style, i'm trying to figure out how to draw that too. again, it's just take screen caps and referance them, drawing them bigger, figureing out how the bunch of crcles do together to make the basic shape, then adding the real lines over the guide lines. once you undersand how the shapes are made, it gets really easy.
as to the drawing straght on the computer, i can't help you thre. i suck at drawing with a mouse, and i can't use a tablet. but i have been able yo draw pony bodys with the pen tool in PS onto heads i'd drawn on paper and scanned in. again, it's just visualizing the shape structures and building it up.
i hope some of that helps, and makes sense ^^; good luck with your drawing!
:reaper: Kat :reaper: