The Fine Details
Depending on your situation, the details of recording a demo will be different from case to case. Variables such as the number of players, space limitations, and equipment all play a role in deciding how you'll go about accomplishing your task. Here are some common scenarios and ways to work with them to the fullest.
If you're working by yourself, it's a little easier to get organized because there are no other schedules to organize and generally you work when you want to. As most recording sessions do, you should probably start with a drum track. If your music doesn't need drums, find the track that has the strongest rhythmic elements, such as a strummed acoustic guitar, for example. Recording those elements first will give you a strong rhythmic base to lay the other tracks on top of. Once your rhythm tracks are down, there's no set order to how you should record the remaining tracks, although many people like to record the vocals last. If you use the studio as a compositional tool and write as you go, you might go about this process differently, and that's just fine—whatever works for you.
There's no set way to make a record. Everyone works differently. Find out what works best for you and work it to your advantage. If you're a night owl, make sure to invest in some soundproofing so you can work at night with disturbing your neighbors and family.
Group demos require a little more planning because you'll likely have more technical hurdles and variables to deal with. One such hurdle is equipment. Suppose you picked up a home studio for yourself and joined a band later. Your current gear might not be the best for group work. The big question is, will you want the band to play together, or do you want to do it track by track, one player at a time? A few things influence this decision.
Do you have the space for a live demo? For many, fitting four or more players plus live drums into a recording space isn't a possibility. Even if you do have the space, can you capture instruments well enough to minimize bleed-through from microphone to microphone? And does your recording equipment/interface allow enough simultaneous inputs? Once you start recording a full band, you enter the “big leagues” of home recording, and the equipment that accommodates this can be expensive. You might be forced to record one or a few instruments at a time, building up a multitrack arrangement if your gear is limited in this fashion. Don't worry; many big-name albums are produced this way by choice, not by limitation.
Multitracking One Player at a Time
If you need to record one player at a time, there are a few things you can do to help you start smoothly. First, record the drums. You will thank yourself for having a rhythm track down first. Bass guitar usually comes next. Then you can record the guitar and keys, finally adding in the vocals. The hardest thing about recording a group track by track is a certain feeling of disconnection when you split a group up like this. After all, you don't rehearse this way! Some of the magic and interaction between players can be lost. It's hard to get a vibe and a feel going when you break up the instruments, but the feeling of disconnection can be overcome. On the bright side, one player performing at a time means the overdubs and mistakes can be fixed with much less hassle.
When recording any direct instrument—one that doesn't use a microphone—nothing says you can't have the rest of the band playing along. Since there are no microphones involved, you won't hear the other instruments on the recording. Having the other players there might help the feel tremendously.
Using a Click Track
Do yourself a favor and record with a click track, especially if you multitrack your demos. Live bands can usually regulate a good tempo together, especially one that breathes naturally, but when you take that element away, you might need a click to hold things together. In addition, it will help lock everything together anyway!
If you have drums, use the click track when recording the drums. Once that track is done, the click is no longer necessary because the drums act as a click from that point on.