You don't need to do something unbelievable to be great. Don't let yourself get into this mindset that you need to keep up with the Joneses. Do something that makes you happy, that is the real measure of success.

The reality is that no matter what you do, even if you do it great there will always be someone better. So you have to do something because you get enjoyment out of it not because your peers approve or because it might garner some praise for a few minutes.

You're young. Yes you are. 30 is a great place to be and for most people the real beginning of their careers.

If you have your heart set on building something cool/useful/etc then you just need to focus (don't beat yourself up), just focus. Look at the list of things you have and pick 1. Don't do any other projects (other than work of course) until you finish. You'll find that in a year from now you'll have plenty to be proud of and that's not bad for a 31 year old.

Good luck.

PS. I found this article very helpful when I've had these same thoughts: http://techcrunch.com/2011/12/03/how-entrepreneurs-can-incre...