When launching a new ad campaign. Whether it'd be search or display - how do you know whether it's your banner / paid search keywords / landing page that sucks OR whether it's the offer(s) that suck OR the traffic source / placement?
You figure this out by testing more
-Don't test one banner, test 10
-Don't test one angle, test 5
-Don't test one LP style, test 3
for offers and traffic sources, you can cut this down simply by picking proven offers and running them on proven traffic sources for this type of offer, this way if it's not working it's probably because of you. Ask your AM for this information.
Proven traffic sources might have shitty placements still, but yea I get what you mean.