In no limit holdem, scare cards are even scarier than in limit. When the flush draw hits on the river, or an Ace hits when you have KK, you run into trouble. The problem you face is that you don't really know whether your opponent's hand was completed. You don't really want to just check every time because that leaves you open to him bluffing. Likewise, you don't want to fire another bet into someone who has you beat, risking more chips than necessary. And, you still want to make money when you have the best hand.
One trick I've learned is how to make a defensive bet. The options are:
One option is to just bet some, maybe the same amount you bet on the previous betting round.
What might happen:
Notice how difficult it is to counter the defensive bet when a scare card hits. It's very likely someone who did hit a flush on the turn or an Ace won't bet a lot because they want you to call. So don't be afraid it appears weak.
Additional Information:
As an extension of this, you can bluff the same way, especially if you've made a bet like this in the past at the same table. Say you tried the defensive bet and got to showdown your KK on the river. It makes no difference if it won or not. It sets you up perfectly to pull a bluff later using the same tactic. Bet a small amount out on the turn or river when a scare card hits (something you could reasonably have). It will be very hard for the players to not take it seriously.