I came across this great series over at GuitarWorld.com by Mark Bacino from Intro.Verse.Chorus. In the article below he talks about how tempo is so rudimentary that it is often overlooked, yet it's an essential part of setting up every song.
As a music creator I (try to) use a metronome on every project I produce. Some are harder than others because many young musicians aren't formally trained so using one is not standard practice (pun intended). When I do use one my metronome of choice is the one included with the iPhone and iPad app, Guitar Toolkit. The app has a lot of features for guitar players, but the metronome itself is very easy to use and it's tap friendly.
Songcraft: It’s About Time
by Mark Bacino
As songwriters, we think of tempo as the most basic of basics. Tempo, or the speed at which we perform a song, is sort of the quiet engine, the driving force behind all our tunes; yet, because we consider it so "Songwriting 101," tempo can sometimes become songcraft’s sadly neglected middle child.
The hard, cold facts are these: Perform a great song too fast and you’ve lost the race. Play a great song too slow and the only animal left in the barn when you finish will be the turtle you rode in on. Your audience may never intellectualize your tempo miscalculations, but they will certainly feel them and sense something’s "off."
Before you begin to record those new songs with your band, have all your tunes' tempos decided upon and documented via the BPM (beats per minute) standard of tempo measurement.
This is great advice. Along with figuring out the tempo there are three other bits of advice I have for you. They are:
Rehearse these set tempos constantly. They should be second nature to the entire band because once recorded and your fans have a feel for them they will expect them come showtime.
Another tempo-finding hack I’ve employed goes like this: Think about your new song and try to recall a favorite tune from another artist that might have a similar vibe or feel. Dig out that artist’s track and try and figure out what tempo their song lives at. You can do this by using the "Tap" function in your DAW or app.
The same thoughts apply. Before leaving that dingy rehearsal room and stepping on stage, try and get your tempos in place. If your drummer is tempo-challenged (and a bunch of good drummers are, believe it or not), they make a lot of tempo-keeping gear for live application that can be used as an on-the-fly reference. If you can, use these tools. They will stop you from playing that 45-minute set in 15 (Been there, done that).
For more on the subject of tempo see Mark's article at GuitarWorld.com.