This is a followup to Proffate's "Voice Acting for Morons" and Doyvid's "Sound Recording for Idiots". My focus is on making the recording environment as comfortable as possible, to reduce distractions and detractions. NOTE: You don't have to be a dickhead for this to apply to you, but it helps.

1. HEAT
This is not to do with giving such an awesome take that the microphone bursts into flames (though if you can do that, kudos and make a youtube video of it). Doyvid advised closing off the recording room and covering the computer tower with blankets to reduce ambient noise. I'd like to point out that while this shuts unwanted noise out, it also shuts unwanted heat in. In our early years there would be four of us in the one room during takes, and with the doors and windows closed and everything else covered in blankets, it got dizzyingly hot very fast. So take care to step outside for air and ice after every few takes, or else all you'll get is a bunch of recordings of people passing out (of course, if that's what you're going for, light a few flares to move things along).
2. DIET
Believe it or not, what you eat and drink prior to and during recording sessions can drastically alter your performance, and usually not for the better. There are exceptions, such as if you simply cannot master THE GRAVELLER, gargling a glass of coke can help, but you won't be able to do any other voices for probably a few hours. Generally it's best to avoid all foods that can modify your voice and sadly, this includes everything fun.

Dairy is out. It increases phlegm production, which ends up reducing your vocal range, not to mention forcing you to stop in the middle of takes to clear your throat over and over.

Similarly, anything with a lot of sugar, soft drinks (or soda for you Yanks) is a bad idea. It corrodes your throat lining and the sugar mixes with saliva to form a thick syrup in the back of your throat. Chocolate is banned for a similar reason.

Stuff with a lot of salt, such as chips and biscuits (or crackers for you nonconformist dicks) will dry you out and sap your voice.

Basically the only thing I can truly recommend is water and plenty of it. It keeps you cool and hydrated and it clears your throat of minor food particles that are impairing your performance.

3. ACTING
I would pretend to be the world's greatest actor, but then all the Alan Rickman fans would poo in my letterbox. I'm actually a bit hit and miss when it comes to Voice Acting, but I've identified the things I did right on my best sessions, and I'd like to share them with you.

As Proffate said, you need to get into character to make it convincing, but this can be easier said than done. I find it helps to pick a voice in your repertiore of quotes from TV and movies that best fits the character. Start off by saying some of your best quotes from that character, and then once you're into the voice, start trying to speak in basic conversation. If the voice you're using isn't quite what you need for the part, gradually modify it here (I'll go into detail on that later). Once you feel ready, then start reading the lines. This helps ease you into the voice, rather than jumping in cold.

We all mimic famous voices, from Don Corleone and Tony Montana to Krillin from Dragonball Z having a feargasm. And in doing so, we speak from different parts of the throat without even realising. Well next time you're rattling off some quotes, pay attention to the parts of your vocal area that are being used. You can usually feel them vibrating, or notice a large part of your mouth that isn't even moving. Once you become aware of these things, you can divide up a voice into its various parts. For example, to test this I just tried out Don Corleone with an Aussie accent, but keeping the effect on the throat that makes him him (though it's friggin' hard to maintain; I keep slipping back into Brooklyn).

If you're really having trouble with feeling confident in a role, try a bit of body language. I know it won't show up on the recording, but it'll get you into the character. I feel much more confident doing a basic American accent if I'm leaning on one leg and pretending to chew gum. I don't know if I sound any better, but it's a good way to at least get some takes done, without having to continuously stop and refind yourself.

With accents, if you feel that your mouth is moving differently to how it normally would, chances are you're on the right track. Watch how people from other countries speak, then try to copy it. And it's not just accents, either. I know I keep bringing up Don Corleone, but this should be the last time. Take a look at him. His face is almost a mask; it barely moves when he talks. And if you're doing the voice right, you'll find you're speaking from the back of the throat, your lips are barely moving, and some consonants are left out, as they're harder to pronounce without moving your mouth drastically.

CONCLUSION
I fear I'm starting to repeat myself, so I'll wrap this up. The key to getting into a role and staying there is comfort. You need to be physically comfortable in your environment, to not have any food blockages or corrosion, and to be comfortable within your own head about what voice you're doing, how you're going to do modify it, and if there are any stances, behaviours or facial expressions that will help you.