Badly Incompetent Baddies

If you watch enough action movies or TV series, you'll notice the hero mowing down the Evil Overlord's minions like it's nothing. For their part, the minions tend to do things like shoot anywhere but where the heroes are standing, wait their turn to attack instead of piling on to a hero they massively outnumber, and falling for obvious ruses. Then again, this could be down to poor management, since a disturbing number of Evil Overlords create wildly impractical death traps, divert resources away from practical tasks to 'evil for the lulz' activities, and blurt out their schemes to inadvisable audiences.

This is rather a shame, since a good villain can often be the driving force behind a story. Their role is to push the heroes outside of their comfort zone. If the story is going to be at all suspenseful, the heroes have to be in real danger, and the Evil Overlord has to have a high probability of winning, right up until the last moment. The best, scariest bad guys are pragmatic and highly competent.

Now although I'm talking about stories which fall loosely into the adventure genre (fantasy, action, etc), but this concept also applies to other story types-- this could be the romantic rival who falls glaringly short of the hero (or is just a bad match for the love interest), the coach who would rather compromise team performance than let the hero play, and so on.

The key is to trust your heroes to come through via their own ingenuity and strength, rather than insuring their success by artificially undermining the villain. The accomplishments of the hero will be much more exciting and impressive when they're pitted against someone who's a genuine threat.