First of all, to attend Stanford Economics is very difficult! Do not feel so dismayed - it is not a reflection on your ability to be doubting your acceptance rate. We have incredibly qualified students each year who are not able to surmount this very high bar: you are in good company.

Second, when thinking about a school like Stanford and how to stand out, the key is to focus on your level of success, not your number of initiatives. Stanford will be impressed by the size of your business (# of customers, # of people affected, etc.) more than anything else and so to increase your odds of acceptance you have to focus on building it as large as you can be. The SAT will be a good check on your intelligence but they prize entrepreneurship. Any hacks to increase your user base / increase branding are important too.