‘Crowded’ websites are difficult to read. Complexity often makes users uncomfortable. If we’ve overwhelmed them with lots of different information, all fighting for their attention, they will leave or not take the action we’d wanted them to do. It may be purchasing something on e-commerce website or reading the article on a blog.
Force yourself to get into the habit of framing up any design you do with what problem you’re solving for people, how you’d know if you were successful, and why your solution is an effective way of solving that problem, and not only will your work be better and more focused, you’ll find it’s easier to get everyone else on board.