I've started using a shotgun approach myself - targeting good churn offers as they come up without necessarily having a plan. I did target Citi/AA to get three tickets to Ireland since their fall saver awards are cheap and I was able to do it with two credit card signups. I've also grabbed good/targeted offers for Southwest, Delta, Amex Gold, and United. I've also been working Chase UR and Citi TYP. I don't mind picking my travel based on what I have points for vs. a must see city.

I basically:
1. Watch for good offers
2. Plan to meet minimum spends based on normal spending - don't want to MS much.
3. Don't poke the same bank too quickly and too often.