Anyone can draw what they see BUT is what you're drawing accurate and proportionally correct? If so, then experiment with dynamic poses and things you can come up with your head. But while I'm here, I want to point something out to you about drawing from reference.
Let me tell you my journey of 2D Design, Beginning Drawing and Life Drawing in a nutshell. All three classes range from Beginning to Intermediate difficulty in the art world. While all three classes did teach me different, but incredibly important, fundamentals for drawing, all three of my teachers told me to do the same thing over and over: Look at something and draw it! You may be pondering why the hell they want us to do this, over and over again instead of having us draw something on the fly? Well, until you acquire the fundamental skills to recognize what makes a drawing, you NEED to continually draw from life until you know the basics inside and out.
Think of it like sports: An athlete needs to continually train their body and mind to keep up with the physical demands of whichever sport they've chosen to be a part of. If they don't take the time to do the fundamentals until they know it like the back of their hand (such as stretching, corrective dieting, optimal exercise routines, rules, etc.) then they'll be hindered in what they do. If they didn't properly know the rules, they'd easily be kicked out of the game. If they didn't know how to stretch properly, they'd most likely acquire an injury faster than you can say "Bob Marley Loves Chewing Gum."
Now why the hell am I telling you my life story? Well, because no matter what you do you'll never really get away from drawing what you see no matter how skilled you are. You can't remember everything you've seen throughout your daily life and more often than not you'll most likely draw something from a reference shot before creating your own variant. It's difficult to create something simply by the willpower of your imagination BUT it becomes much easier to do so once you've acquired a good sense of how things are built in the world.
Alright, I promise we're towards the end of my advice column This is the last tidbits of advice before I go and throw myself into bed. First: Visit Ctrl+Paint and check out Matt Khoer's Traditional Drawing section. He's the best (known to me anyway) source of advice when it comes to fundamentals in video format. The next suggestion I have is to READ A BOOK! No seriously, you're going to read a book sooner or later so why wait? See if some libraries have some fundamentals books lying around. One I would personally suggest is Drawing On The Right Side of the Brain by Betty Edwards. I know, this is boring stuff, but before you can start drawing firefights and epic scenes, ya need to get the basics down my friend. A strong core foundation will benefit you for your years to come in drawing.
Ok, I'm done, paragraph ends here now, I SWEAR, COMMA SPLICE!
I LIED! If you begin to approach the point where even dynamic poses pose no threat to you then I highly suggest studying photographs of actual horses and ponies. The show simplifies everything, without a doubt, so you'll need to rely on actual photographs or horses/ponies before you to get an idea as to how one accurately depicts values for these equines.
I LIED! Part 2: Visit my signature, give the links a shot!