Don't worry too much about the "brilliant people" that may or may not be competing with you. I've never heard of a startup failing because of competitors. At the beginning you aren't competing, you're trying to get traction. Only once you have a product, once you're making money, once you have customers can you have competitors. Most startups fail before this point.

The second part is the fact that you seem to think startups are full of brilliant people. Some tech-oriented ones might (ones that are working on something like building a new database) but most aren't. Most have pretty horrific code quality and manage just fine because your customers won't ever see the code and if they stumble across your source they wouldn't be able to tell the difference between good and bad code anyway so they don't care. At all. All they care about is whether you solve a problem they have and whether it's worth the cost (even free products have a cost: the customer's time).

Find a problem worth solving, solve it the best way you know how and put it out there. If it's a problem people have they will use it. If it's helpful they will continue using it and give you feedback on how to improve it. Listen to your customers and iterate.