In this sample video from Missy Raines' online double bass lessons, she shows what a bass player can do to embellish what the other musicians are playing. 

Whether it's the vocalist singing a melody or another instrument playing the lead, there are lots of different options you can do to create a dynamic within the song.  Your role as the bass player is to be a team player, so you should think about things you can play that will make the lead voice sound good.  

Playing bass is often a selfless experience, it's not about you! This is a big pill to swallow for some bassists, but it's a really important lesson to learn.  

Your role is to make everyone else good while providing the low end of the music spectrum.  In other words, you don't want to distract from the melody with the rhythm parts you're playing.  Think about how can you make what's going on in the song better with what you're bringing to the table.  This is the kind of mentality which will make you a better bass player. 

There are a few different double bass techniques that will help with this, one interesting technique is the percussive slap.  The percussive slap can add an interesting dynamic to the song, especially when used properly.  Remember not to override someone's solo with what you're playing, you want to compliment the music as a whole without distracting from the other elements. 

Visit www.missybass.com for more free double bass lessons and to find out how it works at the Bluegrass Bass School with Missy Raines.