There are definitely some tricks for coming up with a solo on the fly for a song you've never heard before. Of course, in bluegrass or old-time, how different can it really be, right!?

Say someone calls a vocal song in A. It's very helpful to be able to follow a guitar player's chords so you can see when they move from the A to the D to the E for example. If you can follow along, just get your right hand into an easy rhythm and play the root of those chords as they pass by.

The next time through, try to make each one of those notes a doublestop by adding another note from the chord. Doublestops are just any two notes from the chord tones (the root, the 3rd and the 5th). You can either know these notes or get familiar with the positions around the neck that form doublestops. On an instrument like the fiddle or mandolin, you can move all these positions around the fingerboard.

The next time through, try to move between two doublestops for each chord. On a fiddle or mandolin, say you started with an open A note on your A string and added an E note on your D string. Move back and forth every two beats between that doublestop and another with a C# on the A string and the open E string. When the chord changes to the D, you can use the same "pattern" on your G and D strings (doublestops open D with A on the G string and F# on the D string and open A).

Now, think of an instrumental tune you know in A and start trying some phrases and notes from that, knowing you can always return to one of the doublestops you've found if you feel lost. You're coming up with a solo on the fly!

Of course, the real goal is to find the melody on a song and there are tricks for that of course as well. More to come on that...