Lots of writers love their protagonists so much that they can't bear to be hard on them. This is a huge mistake. You will not have a good story if your hero is so superlative that nobody can match him. Whether it's a hero or heroine, the same rule applies: Your villain must match in strength and wits.
Think about it-- your hero conquers whatever or whomever his challenge was, but it was a man of straw, someone anybody could have defeated. Not much of a story, is it? You need to make your villain as vile as your hero is wonderful. Make him even stronger if you like. Make him relentless, formidable, diabolical. Make the reader wonder how the hero will ever prevail against such a terrible opponent. Now you have suspense and the interest of your reader.
Even in a comedic chick-lit book, you have to remember to balance the protagonist and the antagonist. In "Sisters in the Mix," I created a woman who has OCD, hosts a cooking show, corrects grammar on public signs, and wants a world of neatness and order. Who descends into her structured little world? Her nemesis--a flaky, bohemian artist sister who undermines her parenting and even wrangles her way onto the cooking show. Each is as strong as the other as they butt heads.
And remember, nobody is all good or all bad. Give your hero flaws, and give your villain virtues. Then it will not only ring truer, but it will give each character room to grow and change, for better or worse.