Why now, why is this the perfect time for this particular idea, and to start this particular company?
The idea should come first, the startup should come second.
You need unstoppable people. You want people that are just going to get it done.
You have to find a small market in which you can get a monopoly and then quickly expand.
Two other things that we hear again and again from our founders, they wish they had done earlier, and that is... simply writing down how you do things and why you do things.
You need conviction in your own beliefs, and the willingness to ignore others naysaying.