@Rainbow Dash is best pony  
ok that didn’t take as long as I thought. Here’s my recommendations. the wing is a personal attempt at a more show accurate look, but if you prefer your wing style, no need to follow it.

@GlacierFrostclaw  
Ok.

@Rainbow Dash is best pony  
Ok I can see where you’re screwing up. gimme about 30 minutes and I’ll do some lining to show you what to do to make it look right

@GlacierFrostclaw  
Left one: Using circles.  
Right one: Not using circles.  

@GlacierFrostclaw  
Ok. I’ll work on it now. And check your art out too.

@Rainbow Dash is best pony  
Well if you don’t mind, could you make an example of a pony using circles? I could look over it and make some further suggestions. Take a look at my art if you want an example of using the circle method.

@GlacierFrostclaw  
Um… I don’t usually use circles because even though I do that sometimes, the result looks worse than without the circles. I was kinda planning to make a third attempt…

Second is better, but here are some suggestions to improve. For the bodies, try using two circles. One for the flank, one for the chest. Head would be a third circle. Also make the legs a bit thicker and they should look better. Keep up the practice and reference images from the show when you can.
 
EDIT: Clarification on the circles. When drawing the circles, draw them as lightly as you can while still being able to see them so you can erase them after getting the body shape down.

I just realized how messed up Celestia’s hair is in the first attempt.  
Even though I drew this, I still dunno what that turquoise thingie by Rainbow Dash’s tail is in the first attempt.  
I’m choosing my second attempt over my first attempt.

2nd is better.