Your Worst Enemy Is Yourself
One mistake I see startups make a lot is getting too focused on what is going on around them. They spend too much time trying to figure out what their competitors are going to do. They watch the next hot startup with jealousy and it reminds them of when they were that "shiny new thing" and they want that back.
The reality of startups is that there is so much opportunity out there that if you just focus on what is in front of you, your company will do fine. But focusing on what is in front of you means not focusing on what is going on around you. You need to put blinders on and execute. Do not let what is going on around you whipsaw your strategy and your team.
I am not suggesting that you should put your head in the sand. It is critical to know what is going on in your market. But it is equally critical to have a strategy that makes sense in the context of what is going on and execute it with purpose and pace. If you spend too much time looking over your shoulder, you will not execute well. I've seen it again and again.
So don't let all the news of the day slow you down. Don't let your competitors press releases and launch parties get inside your head. Plan, build, ship, and scale. Assess. Repeat again and again. Win.