My biggest advice to you is to research the
anatomy and the
behavior of equines. I could only assume that you were drawing an angry horse pawing the ground? When I started to get into drawing equine seriously, I would print out stock photos and draw over them with a frame and outline so that the anatomy of the horse would ingrain into my wee little brain ^^ So for an example, The barrel would be a oval, the knees would be boxes, the shoulder would be a teardrop shape, etc. Literally, break the animal down into simple shapes then piece it back together. However, at the end of the day, it all depends on how much effort you are willing to put into it~
Below, I've added many tutorials on how to draw horses.
And lastly, a word of advice, If you want proper lines done, you are going to have to offer way more than what you have thus far.
This is an average payment for good lines without extras, such as shading~