Actually, most of the time, i don't. This one isn't based on a photo or something. Some of my works on my DeviantPage are (2 of my catwomans are and the princess Leia is but that's all). I deeply believe it's a mistake because working with a reference has a lot of advantage, your learn a lot about anatomy, you go out your comfort zone (wich is important) and most of the best artist in history still do it no matter how big theyr carrier and theyr experience are. But i do some practice based on photo reference but not enough to my taste