There is nothing quite like an antagonist that all the PCs can hate together to keep a campaign moving forward. Sure, the villian put fricken lasers on the backs of squirrels and tried to kill the PCs, but what is a villian doing when he’s not tormenting the PCs? Moreover, how do you keep the PCs from killing the villian right away without resorting to GM fiat? Here’s a few best practices I use in my campaigns
Luck of the Devil
Whether it’s metagame traits like Luck or Serendipity, unspent character points, or something like Impulse Buys, a villian you want to keep around for a few sessions should have it. Oops, Uberfuhrerbraininjarrian the Brain in a Glass Jar in a Robot Body failed his HT roll to stay alive? Nope! Didn’t happen. He made it. He uses a character point to alter the roll. Everyone falls prey to bad dice rolls and your villians are not immune to that. Have a way out. A good rule of thumb is to give an important villain (or any NPC really) a number of unspent character points to use per appearance equal to the average point totals of the PCs divided by 200, round up.
Villains Are Not Stupid
A NPC you want to become a recurring villain then play them like a villain – don’t make stupid decisions, assume they are smart enough to deduce where the PCs are at (if they aren’t specifically hiding) and then exploit PC weaknesses ruthlessly. If that’s too metagame-y, use the rules from Pyramid #3/52: Action “Fortunately, I Saw This Coming.” They’re kind of like gadgets, but for scenes. I highly recommend them.
Villains Are Not Alone
A villian you want to stick around should have lots of mooks the PCs can stick with knives. This gives the PC something to count (they killed some mooks) and it gives the villian time to get away.
Villians Do Not Sit Still
If the PCs are doing something, the villain should be doing something. The GM doesn’t have to announce what he’s doing, but he should mention that the more time they take the more time their nemesis have as well. Taking a month off for the perfect plan may be useful, but it becomes less useful when the villain has the same time.
Picking Over The Bones
I’m sure there are others I’m forgetting, but those are the big four that I use for my campaigns. What sort of “meta-game villainy rules” do you have? How did you use them?