Please give advice and critique

[xelfereht]

When doing a "study" (I don't know if I could call what i'm doing that) I always do it the same way, some circles and lines, and then putting stuff on top. All eye-balled. I think I've learned a few things from it, but like you said i'm not getting much bang for my buck. With head studies and stuff like that, should I try doing it from my imagination, or by using a photo? If I don't reference anything, how will I know if i'm getting the placement right? Also, people seem to use boxes a lot, would that benefit me? 

when you eyeball stuff as long as you critique your efforts your'e training your eye, so that's good.

you want to do both from imagination and referenced.
you try to take some information from the referenced study,
you may for example focus on the general gesture, anatomical landmarks, weight, basic forms.. any number of things

then you do some from imagination sketches
you compare the two and see where you are still lacking and there is your guidance for what to be more observant of.

some people prefer boxes, wont hurt to try and if it feels like a nice approach, incorporate it.

peoples approach varies, try them all and see what sticks then try them again once you've grown and you may find use in what you previously did not.