Do I use references for the pose of the body? Absolutely! In drawing a curvy female or ripped male, it's almost impossible to get all the nuances right without some real-life examples to draw from. I spent years worrying that this was somehow "cheating" and I'm here to tell you: get over it. Study anatomy carefully and begin each drawing on your own. When it's time to add details, use references to aid you. I have a large collection of photos categorized by viewing angle (front-on, profile, back, etc.,) and with a combination of these on my drawing table, I have the information I need to refine the character's form.
But I'm far from finished. Stepping back from the art, I see that I've made some significant errors in my proportions. This can happen sometimes when you're drawing at a large scale; because the top of the paper's tilted down and away from you, it's easy to overcompensate and draw things near the top too large. Held at an angle, the art looks fine, but seen straight-on, it's warped. And that's what's happened here; the head's too large and the neck is too long, especially given the low-angle we've got on this character (Fig.03).
So I scan the image and bring it into Photoshop where I can easily transform the scaling and adjust the head. At the same time, I use Liquify to push a few other things, like her shoulder, into a more naturalistic position.
Another helpful trick at this point is to flip your canvas horizontally or likewise hold your drawing up to a mirror. Mistakes tend to jump out like sore thumbs when the image is viewed this way, and you should do it often. In Photoshop, I've mapped the flip command to the F5 key as an Action, and this greatly speeds up the process.
I make one last adjustment to the basic pose, by pulling her right leg outward a bit, and then I'm ready to start on her outfit. It might be tempting to add costuming details before this stage, but I wouldn't recommend it. Make absolutely sure that your pose is sound before continuing, or you may have to redo work later (Fig.04).