instand1 - 11:35 pm on Feb 18, 2013 (gmt 0)
1) best way to find negative keywords, imho:
In AdWords under the index tab "Keyword-Details"
Select all keywords for a long period, say a year or so. Then remove all obvious junk and those keywords that have a low conversion rate.
2) Display network: you can select only those placements with a high conversion rate. Automatic placements can be switched off completely after an initial "trial and error" period.
(Can be done only seperately for each ad group.)
3) Keep search and diplay campaigns separate: Gives much better overview. Use AdWords Editor to duplicate and separate the existing campaigns, if they are mixed.