Whether recording at home or elsewhere, review your setup. This cannot be stressed enough, since budget issues may not allow more than a couple takes to get a completed track in the can. If the singer is present, briefly run through their material, so you can set levels in appropriate places. Make sure that all equipment is connected properly. Check patch cords and cables for fraying, or other signs of wear and tear.
Consider where the vocalist will be situated while performing. The louder the vocalist, the less sensitivity the microphone needs. Use a dynamic microphone, which is less likely to break up under high pressure sound levels. Outstanding examples include Sennheiser and Shure models, with vintage Neumanns---developed during Hitler's Germany---not far behind. These differ from condenser microphones, which are more sensitive, but are equally good at capturing a decent signal level.
Eliminate as many extraneous distractions and noises as possible, so that stray sounds do not get accidentally caught on tape, unless that is your intention. Use a plosive, or pop filter, to prevent wild consonant sounds---like those beginning with the letter "p," for example---from spoiling a take. Commercial filters are available for $20 apiece, or you can build one of your own for a fraction of that cost.
Position the singer at a 4- to 6-inch distance from the microphone. Make sure that the singer understands that she does not have to "eat" the microphone---standing too close may cause the sound to distort. Standing too far back, on the other hand, can result in too distant a sound. Make sure that the singer does not greatly deviate from her chosen position, because even slight movements can greatly affect the resulting sound.
Watch decibel levels closely while the vocal is being recorded. Zero is considered the peak level, which makes it important for the engineer to keep the recording needle from bouncing too far within range of that number. In general, a range of -6 to -10 decibels is considered optimal for getting the vocal down properly.
Minimize the room's impact on the recording process. Keep the singer from standing too close to the walls, or in the center of a room--because sound waves are in phase, and may exaggerate the room's natural resonance. If you still hear a "boxy" or dead sound on the take, try soaking up the sound vibrations with curtains or drapes. For best results, hang them directly behind the singer.
Encourage the singer, and adjust to his needs. Some will insist on headphones, while others will wear them with one ear off to help themselves pitch better. In that case, switch off whatever side of the headphone is not used. Otherwise, ear-piercing feedback may come through the microphone, and into your headphones. If the singer is recording in an isolation booth, use the talkback microphone to regularly communicate with him.
Never underestimate a singer's emotional state, and avoid wearing them down through numerous takes. If a song does not seem to be happening, move on to another one---endless retakes fritter away natural energy. Similarly, keep hangers-on to a minimum if they are not connected to the business at hand. A crowded control room can risks turning a session into an expensive, unproductive party.
Avoid imposing EQ and compression during the recording of a take. Both are interesting effects, but better left to the mixing and post-production process, and leave more options for introducing particular tricks or effects to brighten up the final take. For even greater contrast, experiment with natural echo--such as by using bathrooms as a vocal booth, to take greater advantage of their natural propensity for reverb.