Apologies for not writing very much lately. I currently have so many on-going projects, I'm struggling to find the time to write-up the many ideas I have in my head. I promise to write up some of my post ideas as soon as I have a bit of free time. In the mean time I have just discovered a blog series by David Sonnenschein that considers using sound effects in sound design. Worth a read if you are new to the field:
http://www.prosoundeffects.com/blog/category/david-sonnenschein/
I'd also strongly recommend checking out David's book - Sound Design: The Expressive Power of Music, Voice and Sound Effects in Cinema.