Doing it All Yourself
The problem: We love nothing better than seeing the clever projects that couples come up with to make their weddings unique. But even we have to draw the line somewhere. There's doing it yourself, and then there's overdoing it yourself. After all, there are plenty of benefits to DIY. You can be sure no one else has the exact same thing, you might keep your budget in check, and (before you actually sit down to hand-tie 200 tiny ribbons) you probably think that it will make a fun story.
The solution: Rather than taking on too many projects, pick the one (or two) that you're really in love with and put your resources (both mental and monetary) into working on those. For the others, do a little research and try to find a ready-made version that makes you happy. With so many great prefab goodies out there, chances are you'll find one that fits your style -- and saves you a whole lot of time!