I am inclined to say that the planning stages of audio creation are the most important and pivotal to the overall outcome. It is during the planning and research stages that you allow your mind to explore the different possibilities. If you just dived into composing you could get so focused on the music that you wouldn't pay attention to the timbres being used and what would best suit the game.
During this planing stage references are incredibly helpful. In the early stages of speaking about the audio for Black Shuck, Chromium Gamesroom were very clear about references. As well as providing musical references they also sent through images so a grasp could be taken on the environment of the game. All of these helped a great deal. Such images can be seen on their website - http://www.chromium-gamesroom.com/BlackShuck
Reference images, music and key words allowed me to start putting a sound palette together. Knowing the game is set in the Georgian Period gave me the ability to utilise instruments of that period. But rather than just using them as they are it was more interesting to implement some audio production techniques to help them suit the game better. This will be further demonstrated in future dev blogs.
The topic of references again harks back to that of good communication between all people involved in the project. Being able to communicate expectations and ideas clearly is critical to success in every walk of life. This is especially true when working as an outsourcer and not always being in the heat of the development so to speak.