To come up with an excellent pr plan, personally, I would start with tactics. Smart clever tactics that initiate actions from the audience is the most difficult to come up with. Once a feasible idea comes up, everything else (strategy, objectives, target audience) will fall into place. Of course, the tactic must first be able to meet the goal.

Personally, tactics are most important to me because Singapore is a metropolitan city. Every single day, people are spammed with adverts, promotional articles etc. I find myself ignoring since they are all useless to me in some way (if I want something, I know where to get it, hence, I dont need adverts). So when I see something clever that is able to grab my attention, I am impressed. Here are a few more examples that I grin at:

http://www.droga5.com/ (many videos under case studies that show what was done)

http://pb4000xl.com/ (Pervert Designs case studies under archives)