There is nothing inherently wrong with loose drawings. In fact, many artists create incredibly beautiful sketches that look effortless. When I look back at my older drawings from art school and before, however, I notice some of the sketchy lines in my work were due to hesitancy rather than confidence. I would often leave lines alone that should have been better defined, or fail to clean up unappealing "chicken scratch" that did not inform the drawing. When I worked in the 2D art department at The Franklin Mint, I quickly learned the importance of tightening up my work so that the next person down the line could read it and do their part to turn it into a product. I grew a lot as an artist in the year and a half that I worked there, and due to the sheer number of drawings I produced, my draftsmanship improved quickly.
One of the techniques I learned while working there was how to clean up, alter or refine a drawing using layers of tracing paper. This idea might seem antiquated since you can do the exact same thing with layers in Photoshop, but many of us in the studio still worked primarily traditionally. Despite becoming much more adept at Photoshop in recent years, I continue to frequently use this technique. The benefit is the ability to scribble out a lot of ideas without losing the original sketch or making a mess of it by erasing and re-drawing over and over again. Instead you clean it up in steps as you layer tracing paper over the top of each previous drawing.
The Explorer's Guide to Drawing Fantasy Creatures. While this is most useful when working with a really complicated design, I sometimes still use it for simpler ideas such as this. I started with some roughs. The most important thing I wanted to get across in this drawing is the pancake shape of the flying critter.
I blew up the rough I liked and printed it out, grabbed a piece of tracing paper, and layered it over the top to begin sketching out a more refined version of the rough sketch. I wanted to take this more realistic interpretation:
closer to this:
Much like someone does when creating a caricature, I reduced the detail down to simpler shapes that emphasized the most essential qualities of the pancake glider. My aim was to make it ridiculously cute.
In this final drawing, you can see where I cleaned up and refined the lines and shapes from the previous drawing. I also took the artistic liberty of flipping the shape of the air pouch on his chest to create a conveniently located heart shape. That familiar symbolic shape just seemed right for the image and made it cuter.