Jayson_Rodda - 3:52 am on Apr 15, 2013 (gmt 0)
Agree - very important to build comprehensive list.
Good tip: Whenever starting an account, people use the keyword tool to add correct keywords into account. Record all of the variations that are also NOT relevant to your account.
By putting these keywords in as negatives to begin with you will save time with ongoing optimisation & save lots of money along the way.