A few years ago, I was asked to lay down some guitar tracks for the symphonic progressive rock band Glass Hammer. Their music is quite dense and very much based on layers of intricate orchestrated instruments. The challenge was to come up with some guitar parts that would be interesting, yet not taking over the orchestrated work that had been done prior to the guitar addition.  

Whenever you find yourself in such a situation, I listen to the part I am given many times and try to find the element that is primordial to the song. In this case, it was the melody. However, in some cases and depending on what appeals to you it could be something else. Maybe a bass line, or a particular rhythm that you find interesting. Once you have the element you like, try to embellish it with your instrument. 

The key is to not think in terms of what your instrument's limitations, but think more in terms of how you can make something written better. Sometimes, the answer is to not play at all.  

There is no particular key to this song, as I'd like you to focus on what you hear, not on what a particular scale would tell you to do. Memorize the given lead slowly with precision, then try to put yourself in a position where you would be asked to play something original on this track.  

Special thanks to Glass Hamer for provising the original track heard on their latest album "Cultures of Ascent".