Recording

In the recording studio the current vogue is for the singer to be very close to the microphone. This helps to cut down on unwanted background noise from other instruments or 'spill' from headphones and also reduces the acoustic ambience of the room.

Given today's increasingly cheap technology such as digital and convolution reverbs you would think that it's best to get as 'dry' a recording as possible and then 'wet' it (a term for adding reverberation or other effects) with artificial reverb at the mix stage rather than to struggle with overly 'wet' recordings that are impossible to get back to a 'dry' state without obvious artefacts.
The problem with close mic'ing is that it's always a very intimate sound, every tongue, lip-smacking and breathing sound is picked up by the microphone and if the microphone is looking upwards towards the nose it can also sound a bit more nasal in tone.

The contribution of the chest cavity to a vocal sound shouldn't be under estimated, it helps to warm up the sound, so backing off the microphone by several feet will help to achieve this. This makes sense really, when you think about how you normally listen to singers, you hear them in the room, not right next to them.

The problem with putting the microphone further away is that you hear more of the room's acoustics and in a small studio or vocal booth it can sound 'boxy'. To reduce this effect you'll need to hang sound absorbent materials such as curtains or duvets behind the singer in particular, since this is where the microphone is picking up most of its sound, and on other walls until you have a suitably 'dry' sound.

Microphone
There is no particular microphone you should use when recording lead vocals unless your vocalist has a very quiet voice, in which case you'll probably have to use a condenser microphone to avoid too much hiss being recorded.

If the singer has a very sibilant sound then you might like to experiment with a ribbon or dynamic microphone to reduce the high frequncies. Make sure you use a good windshield with a ribbon microphone as it's prone to damage when blasts of air hit the diaphragm.

Usually a cardioid pattern is selected to avoid picking up unwanted sounds from behind the microphone, but it's also worth experimenting with pickup patterns e.g. omni to see if you like a bit of the natural acoustic of the room to be recorded as well. The cardioid microphone works by combining two diaphragms which cause some out of phase artefacts, so in fact the most natural pickup pattern is the omni pattern. Ultimately you have to use your ears to decide what works best.
If the microphone has a bass roll-off switch then you should be able to use 75hz to help reduce any mechanical knocks to the stand or foot tapping on the floor. Use of the 150hz postion risks making the sound bass-light. It's worth putting a carpet under the stand and the singer's position if there isn't one there already.

If you decide to position the microphone several feet away from the singer you might need to put up another microphone with a windshield infront of it close to the singer, they will think that they are using it. This prevents them from getting ever closer to the real microphone, which they will, inspite of your instructions.

You could record both microphones on separate tracks and decide which one you like best later, alternatively use both of them, the close one for quiet sections and the distant one for the loud sections.

Different microphones suit different singers so experiment a bit while they get used to the track. Put out a handful of microphones if you have them and listen to each one to find out which is the best, then remove the ones you don't like along with their stands to avoid cluttering the studio.

Conditions
Making a singer feel comfortable is very important. A song usually succeeds or fails on the strength of the vocal, the listener needs to empathise with the vocal. If the singer feels good then they will give a better performance than if there are technical problems i.e. they don't like what they are hearing in the headphones. It might be a good idea to offer to screen them away from the control room, since the sight of people chatting or laughing on the other side of the control room window can be unnerving for first time vocalists, they might think you're laughing at them, no matter what you say to reassure them on the talk-back system.

There is a certain amount of psychology involved in getting a good vocal performance, some singers know what to do and when they've achieved it, others need lots of encouragement and directing. Sometimes you'll just have to accept that the singer's not in best form on that day and arrange another time to record.

Make sure that the singer has a comfortable balance between their voice and the backing track and a good overall level i.e. not too loud or quiet and perhaps a bit of reverberation or other effects on their voice. Use 'closed-back' headphones to reduce 'spill' of the backing track onto the microphone.
Some singers like to use just one side of the headphones to hear the track and listen to themselves clean with the other ear. Make sure that they keep the un-used headphone completely in contact with their head to avoid spill. There are single sided headphones available or you can pan the mix to or at the headphone amplifier on one side only.

If you're in a home studio ideally you will have access to a separate room for the vocalist, if not you'll have to record vocals in the same room as all the recording gear, so you'll have to wear closed back headphones and mute the speakers during takes. Be aware of machinery noise getting to the microphone, use an absorbent screen between the equipment and the microphone if you can.

Mixer/pre amplifier settings
Whether you use a mixer's microphone channel with a patched in compressor/limiter or a separate 'voice channel' (pre-amplifier, compressor/limiter and sometimes equalisation) it's best to record vocals without too much processing i.e. equalisation and compression, just concentrate on avoiding hiss (too low a level, particularly if recording on analogue tape) or distortion (too high a level, particularly if recording digitally) since both are difficult, if not impossible, to remove afterwards.

You can use compression but only at low ratios, and/or a limiter set at a high threshold to stop the loudest moments from distorting. Don't record effects (unless it's on a separate track) or use an electronic gate, leave these to the mixing stage. Like overly wet signals, heavily compressed tracks can't be uncompressed.

If you have enough spare tracks record all the takes, including the warm-up ones, since this might be when the best performance is given before the 'recording light' goes on. Some vocalists do suffer from nerves when they think they're going for a real take but are at ease when they think it's just a rehearsal. Also the early takes are usually the best ones before the singer's voice gets tired. Later you can compile the best bits from various takes onto one track.

If the singer isn't giving a suitably powerful performance it might be because they are hearing too much of their own voice. Reduce the volume of their voice in the headphones and then they will sing louder and hopefully with more feeling.

Try to have as near a finished a mix of the backing track as possible for the singer to listen to, then they will have a good idea of where they fit into the mix and you will be able to hear if the track is too busy in parts, rhythmically or frequency wise.