I love this line shared by author Terry Montague. She posted it at a writers’ forum back in 2005: “Your story is built on the strength of your antagonist.”
How profound that is. How many stories have been spoiled by an unbelievable wimp of an antagonist, barely able to further the intrigue of the plot?
In other words, your ‘hero’ should have to work to win. If you want to spice up your current novel, see if you can’t intensify the ‘badness’ of your antagonist. It makes the story more nail-biting as your protagonist fights against a nearly unbeatable enemy.