And how do you refrain from ripping out your hair in frustration?
But that’s the first step!
Seriously though, it just takes practice. We’ve all been at the hair ripping stage before. Luckily, we’ve got a video on exactly how to retopologize hands (part of the character course that was linked above):
https://cgcookie.com/lesson/retopologizing-the-hands
And if you need a refresher on retopology in general, I’d recommend taking a break and watching through this course:
https://cgcookie.com/course/introduction-to-retopology