Not launching as soon as I could have.
Perfectionism is great and all, but getting to market quickly is more important.
It's the only way you're going to know if investing more time into your idea is worth it or not.
1. Not prioritizing tasks properly.
Figuring out which things to do first (and stick to it) is hard. It's easy to work on things that you find more fun but aren't important for growing your business.
2. Not being able to delegate tasks properly.
It's hard for a solo founder to relinquish control (especially if you're a perfectionist and have preconceived notions that no one would be able to do it the exact way you want it).
3. Trying to please everyone.
It's better to have 100 customers that absolutely love you than 100,000 who sort of care about your product.