Some of this is written especially for Pro Tools, but these tips can apply in any medium...
For artists:
REHEARSE! I know sometimes you want to run into a studio THE SECOND you finish writing, but when you don't KNOW your rhyme, it SOUNDS LIKE YOU'RE READING IT! Few people can actually pull this off with the right accents and such, but there are a few more things you can work on before you hit the studio:
1) Break your verses down and find out the spots where you run out of breath. Underline the next line, or next few words, and choose not to say those in the first take. When you do dubs later, you can add those lines, but make sure you say the last line and the next line to keep you sounding like you did the last time.
2) While you're writing your rhyme, (UH-HUH) practice utilizing the negative space. (NA MEAN?) Write in your actual ad-libs while you write, (TRUE) and when you actually perform it, (UH-HUH) everything will be filled up. (THAT'S WHAT I'M SAYIN' SON!)
3) Practice good mic technique! I know that the engineer probably has a good compressor so that when you yell, it kicks in, and when you're quiet, it pushes the level, but a good technique to become your own compressor is to BACK AWAY from the mic when you yell, and GET CLOSER when you're quiet. Do this in moderation, and even small movements can effect the way it sounds. So practice it... it's worth it!
4) Depending on the microphone, you can avoid sibilance, etc. by turning off-axis from the mic, as posted before. But, with most low-end microphones, this will take away from your high end. And then you have proximity effect: When you get really close to the mic, all the low-end frequencies become really thick. This could be a good trick when you need it (notice Howard Stern and how close he comes to his RE-20) but try to find a good spot depending on the mic. And if there ends up too much sssssibilance, then use a de-esser later on, adjusting variably between 7-10kHz until it "ducks" it right with your set threshold.
For engineers:
These tricks have worked for me to make it as efficient as possible to record and make a client/friend feel comfortable and get the best takes they can.
1) Just like rehearsing for the artist, you should rehearse the song as well. And doing this will make so many shortcuts later on. Find out where the Verses start, and either write down the times, or make markers. (e.g. in Pro Tools, hit "enter") In Pro Tools, getting the right navigation is important, and later on, your mix engineer will thank the hell out of you. (or you'll thank yourself if you're mixing it). Set a good Pre-roll for about 2 bars, and (apple-K, or ctrl-K on PC) will turn on/off your preroll. Now you can hit a few buttons (period-marker#-period) to get to the spot, and hit apple-k and then roll, and the artist will hear the last two bars of the previous hook and be ready for the next verse. Artists can be in the zone one minute, and if you're sitting in the control room trying to find his next verse, he can lose his groove. BE QUICK! Learn how to set your memory locations or markers, whether you're using DA-88 tapes, a 4-track cassette recorder, Pro-Tools, Cool-Edit Pro, or anything else. If you don't have markers, then write down the times that everything begins! It makes it much easier later, TRUST me.
2) When tracking, it's all about LEVEL. You have to try to get the hottest sound to "tape" without clipping for the best sound. (You will get the best "SNR", or signal-to-noise ratio; signal=sound you want, noise=sound you don't want, e.g. air conditioning, the "air" of your preamp, etc.) You don't want your soundwave to look like some little mouse tail, so get it thick, but use light compression.
3) With your setup, find a good setting for compression. (Before you record, mess with the levels and record dummy takes, finding out what compression actually sounds like. Turn the threshold waaay down and set the compression ratio to 20:1 or more. Listen to what it does to the sound level when your talent yells into the mic. And when he/she is quiet. You will hear the compression "breathing". Not just the artist's breath, which you can usually hear better in this situation, but the signal actually sounds like it "breathes". Mess with it and see what I'm talking about.) Now I usually find these numbers to be a good starting point: Threshold -10dB, Ratio 4:1, somewhat quick attack, and somewhat slow release. But since you know what compression sounds like, now you can make adjustments accordingly. Remember: hottest levels without clipping.
4) Okay, now that you have a good level, (pro tools users) create some new tracks and make more than one, and make sure your outputs are set. Your artist doesn't want to wait. NAME THEM. When you name them before you actually record, it will label the actual audio files "Verse_01" or "Vocals_01" or "Johnny_01" instead of "Audio1_01". If you look through your audio files folder later on, you shouldn't see "Audio23_03.L" etc. If they're labeled, it makes troubleshooting much easier later, and if you lose files, you'll know which ones you're missing. I'm not going to get into disk allocation today, but learn that too!
5) Layer for verses. When an artist can lay it on thick, the entire vocal tracks will cut through the record better. Depending on the song, and the hype you want to convey, encourage the artist to have a couple layers be the exact duplicate of the verse, and add layers that are lower in tone, maybe even whispers, or performing it as if he/she was bored, or even more lively than they were in the verse. Prepare to have audio tracks ready for dubs, dubs2, dubs3, etc, adlibs, adlibs2, what-whats, yea-yeas, uh-huhs, etc. You may not name them when you create them, but you can quickly double click on them right before you record. "Okay, you wanna do uh-huhs?" "Uh-huh." (name them) "Okay we're rolling." THAT'S what your artist wants to hear.
6) When doing hooks, layer layer layer. I like to name the tracks as follows before I begin: "HookL, HookR, HookMid, Hook4, Hook5", etc. Have them do hook left in mono, and when he/she performs the layer for Hook right, pan them both so that the artist can feel what it will be like in stereo, and match his/her voice better. This sometimes confuses the artist though, but try it once or ask them if they want it. Have them do many layers with parts that have more energy, try screaming, etc, and be suggestive. Of course, unless they have a producer and he/she's running the show, or the artist already has a game plan. But if the artist doesn't have a game plan, try to inspire a little creativity, and let him/her ride on the hype of what was just recorded. It can create a lot more energy than you think.
Okay, these are just a few tricks that have worked for me, and there are a few more that I can't think of right now, or someone else already covered them. But being prepared is most important once you get the LEVELS down pat.
Hope this helped someone.
-the Hypnotist