If you have a smartphone, use its audio-recording capabilities to capture all the little song ideas you have throughout the day. It doesn’t matter if they’re vocal melodies, little pieces of riffs, or full-blown choruses. This is really only the tip of the iceberg, particularly if you have a smartphone for audiophiles.
Your smartphone really can be a highly effective tool for you as a musician — indispensable, really. And as DIY Musician pointed out a couple years ago, there are some definite ways to use your phone for shooting great music videos as well.

