We decided to overdub vocals to our live instrumental session in a separate session to reduce the risk of mic spill from the other instruments and increase the chance of getting a better instrumental take for the guitarist/vocalist in the band.
This method will also allow for higher quality vocal tracks to be mixed with better results for the overall recording of the song.
It's important to try and retain the live feel of the track you have so far and carry that through with the vocal. Try to record vocal parts you can recreate consistently live and also try to track the vocals in longer segments so the take sounds more like a natural live performance.
The vocalist needs to be comfortable with the music and feel of the recording before even attempting to record. Warming up is essential, so don't rush into recording the vocals after setting up. Try some run-throughs of the song, planning where the best places to stop will be to break the song up and how far you need to be from the mic for specific dynamic parts.
It's worth having someone to assume the role of engineer with you, monitoring the sound and offering a second opinion on whether a vocal take could be approached in a slightly different way for better results. They can also start, stop and erase unwanted takes without you being distracted from focussing on your performance.
We're using a condenser mic to track. There's a wide range of condenser mic's available and advancements in manufacturing mean affordable models can still produce quality results for those on a budget. Nevertheless, we'd advise always using the best mic's you can afford or even loan for your live session.
Condenser mics can be sensitive enough to pick up noise that you won't want on your vocal track, such as traffic outside. Try to choose a location where these factors are minimal or consider a time of the day where it will be quieter. A vocal mic screen that attaches to the mic stand can help filter sound reflections from the room, try to keep away from setting up the mic close to walls to avoid this unwanted effect as much as possible. A pop shield is even more important; helping to reduce the unwanted 'popping' and 'thumping' caused by forming plosives, these can be found in certain words while singing in close proximity to a mic.
It's important the vocalist is comfortable with the balance between their vocal level in the monitor headphones and the music they are singing to; take the time to get this right first. But the vocal sound being monitored back is also vital, if it's too dry it may negatively affect the performance. Using your recording software's plugins to add a little reverb can be very useful for this. Here we're using Steinberg Cubase 8's [specific effects used].
Don't leave fixing for later
It might sound obvious but if there's anything you're not happy with as vocalist or engineer in the vocal take, it's worth addressing there and then, even if it means punching in some lines again here and there that don't sound quite as good as the rest. Don't settle for less than the best because if the raw vocal tracks sound good, it will make the mixing stage much more straightforward.