The process shouldn't be too much different than SD. For them:

• Make sure the subject does not wear white to prevent hotspots.

• Some closely lined clothing patterns can look funny.

• Turn off all phones. Throw away all cellphones (my cheaper wired lav picks up cell interference).

For you:

• Make sure the subject does not sit in a chair that can spin or pivot or have wheels.

• Use some of the powdery makeup if needed to tone down face shine.

• Check focus for each subject.

• You will always need more light than you expect.

• Use a lav mic and a boomed shotgun mic for good audio.

• Have an assistant.

• Avoid multiple light sources so the color temperatures don't conflict.

• Make a checklist of all the stuff you need.

This list can get huge. Good luck at your shoot.

• Double check potential interview locations so there are no surprises.
• Avoid places with a lot of activity and background noise and movement unless that's part of the interview. This will look especially weird if you have to resort to making jump cuts and people in the background are appearing/disappearing.
• Although not always a factor you should find a place where you can shut off the AC or heat if its making too much noise.
• Record a minute of room noise after the interview is done.
• Give your interview some depth and avoid having you subject right up against a wall or backdrop.
• Shoot some b-roll of your subject like their hands to act as cutaways, you can also shoot some b-roll of the space or interviewee as they are getting mic'ed up (if you have a crew). Request five minutes of their time after the interview to go through actions they perform at work for more cutaway options.
• If possible use two cameras. Lock down a wide shot on one and use the other to move between close-ups and medium shots. If you only have one camera you should be able to recompose your shot and get focus quickly, practice at home. And make sure you shoot footage to cover these moves.
• Don't fiddle with the camera during the shoot. You should check focus, exposure and compositions before the interview starts. If something happens by all means stop the interview.

I've recently made the switch from SD to HD. It depends, of course, what kind of interviews you are doing -- static, locked down, or informal chatting while moving around. The biggest difference I notice is framing. You are going from 4:3, almost square, to 16:9, a wide rectangle. You have room now to use the sides to lead the subject with more space. But you want to think of the final edit so that different subjects are not being slammed from one side to another.

Also, due to the clarity of HD you can be more creative about incorporating background.

• Don't trust the picture to an SD monitor. If you don't have an HD monitor when you are shooting, rely on the LCD or viewfinder

• Watch your shutter speeds it could change to a setting which could make images blurry.

• Learn the camera and check, check, check your settings

• The more you can control your environment, the better your chances of bringing back something you will be happy with.

• Remember, you're shooting in a 16:9 widescreen aspect ratio. This means the picture is 16 units wide for every 9 units it is high. Protect for 4:3 - which means frame your shot for a standard 4:3 aspect ratio.

• The toughest challenge when shooting 16:9 is getting a clean single shot of your subject. You will have to position the camera further off-axis, resulting in a look that is more profile.