Nope, that's about the way I'd start out.
Presumably you'd be willing to pay a little more for the placements that actually convert and give you good ROI. So it would behoove you to keep breaking those out into separate campaigns, where you can bid a little more, and in some cases, create ads that are actually targeting those placements.
Keep running the placement reports regularly; set a threshold for yourself when it makes sense to move a placement from the "general" group to a targeted campaign.
I like to set up a sort of tiered system - at the top are the campaigns that are the very best performers, and they will often only have one or two placements. And I'll actually go visit those sites, and try to get a feel for them before writing ads specifically targeted to that group (or if it's image or video ads, I'll go look at their placements and sizes and what's available and who I'm competing with. You can also use the Google Ad Planner to help with this)
The second tier are the climbers - they've shown good promise, but not quite ready for top tier. I might have one or two dozen in here. The ads are a bit more general (maybe because I haven't had time to spend on the sites)
Then I have one or two lower tiers; one for sites where I get a lot of clicks but not many conversions, and another for ones where I get a lot of impressions but not many clicks. These will run at a lower cost till I get a chance to do something about them - if I'm getting the clicks but not the conversions, I probably need to work on the landing page, and if I'm getting the impressions but not the clicks, then either they're just not a good match (and thus go into the negative pile) or else I need to write better ads for them.
There, there's your whole strategy in a nutshell.