1] Don't be afraid to trace over a photo off the internet to practice. As long as you don't post it with yer watermark on it sayin' that it's really YOUR art that you drew. Because it's not. I mean, you can copy the image and easily claim it as yours, but just say somethin' along the lines of oh I'm practicing so I used an illustration from the official artwork. Start out with a wire frame. That will start you on yer journey to becoming an Equestria Girl. Simply find a pose that suits yer character or one of the main characters, then yer good to go.
2] I'm a perfectionist, that's why there's a lot of places that I wish I could change very precisely. Don't be afraid to make mistakes! It's simple enough to tell yerself, oh wait I fucked this up, let me try this again and again until I get it the way I want it. Adding detail is key! Wrinkles in the clothes to the glimmer in the eyes. Keep that in mind. Add whatever detail makes you happy!
3] When it comes to adding the final edits to a picture, it's always important not to overkill it. I've seen it. Trust me, I've seen worse than a perfectionist like me. Overkilling an illustration's detail might be goin' too far. If it's just one character with a simple design, feel free to spread it out a bit, but if you make every fuckin' area with fifty strokes just to get the point across of a wrinkle in a shirt... don't do it. Add the final detail to the illustration. After that, go nuts with the color! Experiment some!
I didn't add color because I'm a bit lazy right now and it's official artwork, so this photo wasn't mine to begin with. I just used the official art to get the point of Equestria Girls anatomy before I started makin' my own stuff. c:
Pinkie Pie and Equestria Girls (C) Lauren Faust