If you are in a crowded market, you have to stand out to attract new customers. A good way steal competitors' users is to develop the feature they are asking for.

And it's actually pretty easy to find these features. Most SaaS have feature requests pages. All you have to do is find the most requested features and develop them before your competitors.

And to drive the point home, once  you've released the feature, you can reach out to the competitor's users that requested it to let them know that it's available on your product.