Firstly, why are you planning to hand-hold the camera? For purely aesthetic reasons? For purely practical and logistical reasons? Obviously, either or both reasons are legitimate. But please let it be a conscious and informed choice. I trust no TV-2 student, after all we’ve said and seen, would automatically associate hand held cinematography with the documentary form.
When hand holding, remember the basics:
Focus will be less of a challenge, the greater the depth of field.
The shorter your focal length the greater the depth of field.
The more light, the smaller your lens aperture, the greater the depth of field. You might do something as simple as open some curtains or switch on some domestic lighting to effect this result. (But the Maysles would never have done either of these things - these gestures would have come between them and their subjects. On the other hand, I’m pretty sure Humphrey Jennings started some fires in order to “document” the blitz. What kind of documentary are you making?).
You might also, cautiously, switch in some gain in order to use a smaller aperture. (Al Maysles would be O.K. with that. Humphrey might just light another fire. They’re both great filmmakers.)
The longer the focal length, the more apparent any camera movement. People tend to use the widest end of the zoom to hand hold: greater depth of field; camera movement less obvious. Equally, that wide angle, hand held look may not be appropriate. Experiment with how effectively/acceptably you can hold the camera on something other than the very widest end of the zoom. What is the relationship between your desired aesthetic, the practical demands of your project, and your approach (Maysles/Jennnings) to your subject?
Some other thoughts on hand holding:
If holding the camera on your shoulder with your right hand, experiment with steadying the unit with just the tips of the fingers of your left hand on the matte-box/ lens shade.
If walking with the camera, consider the possibility of having another crew member guide you. It might be safer. It might give you more confidence. It might steady you in some situations. Equally, it can sometimes be annoying and limiting.
Relax. Work on a lightness of touch, and step.
Learn to distinguish between what you feel and what you actually see through the viewfinder. Was that big bump we just went over significant on screen? Are these small movement of mine, huge on screen with this telephoto lens?
Further to this, a camera might feel level in your hands, or on your shoulder, but consider the image in your viewfinder. Are those vertical lines (represented by that doorway/that bookcase) straight? Would I expect them to be from this perspective?
Finally, whether hand holding or not, learn to open your non-operating eye - if only occasionally. Note any changes in the lighting conditions. Be aware of that person’s hand gestures that are out of frame. Do you want to include/exclude them? Be aware of those who are about to enter or exit frame. Directors, have a line of sight to your camera operator. If they open that non-operating eye, they should be able to see you and be able to interpret your signals. Camera operator and boom operator should be conscious of one another, and work together.