Any advice on how to decide what key to write a song in?
If you're going to be singing it yourself, choose a key in which the highest and lowest notes won't exceed your vocal range. If it's guitar based, depending on your level of ability, choose a key that won't have you struggling with difficult barre chords - or else use a capo.
if its a sad song, use Dminor, its the saddest of all keys. If you want to be pretentious, try Eb major, it worked for Beethoven.
if you've got a melody in your head, put chords to the melody - they don't have to be anything special, just a couple or three chords. Then try singing along to it - if it's in the wrong key, move ALL the chords up a semitone at a time until you find a key you're comfortable in. THEN try adding different chords in that key....
Say you're thinking G C and D. Too low for your voice. forget Ab - all barres. try A D and E....then keep moving through the scales till you find something that fits.
I find, when I'm writing music to fit lyrics, I always start for some reason in A - A, D, E and F# seem pretty easy to me. I can play a bluesshuffle - A, A5, A6, A, D, D5, D6, D, E, E5, E6, E - pretty easily using open chords. Then I'll try and do the same shuffle in D - I have to move way up the neck to get it right. so I'll compromise - maybe do the song in E, lower vocal register, easier E - A - B shuffle......
It's all about compromise - if you find the right key for your voice, but you can't play the I IV V on guitar, try starting with the IV or the V as the root, or the base chord....
:D :D :D
Vic
"Sometimes the beauty of music can help us all find strength to deal with all the curves life can throw us." (D. Hodge.)