The secret to a successful startup? Don't die.
So I'll tell you now: bad shit is coming. It always is in a startup. The odds of getting from launch to liquidity without some kind of disaster happening are one in a thousand. So don't get demoralized. When the disaster strikes, just say to yourself, ok, this was what Paul was talking about. What did he say to do? Oh, yeah. Don't give up.
In his classic essay How Not to Die Paul Graham suggests that your startup will success as long as you can avoid dying.
All heroic business stories have at least one chapter where everything seemed hopeless. The key is expecting these periods to happen so you can push through them.
Grit inevitably leads to success; if you don't die, the only other outcome possible is victory.