Once you realize it's all nonsense, it starts to make sense.
All big things grow from small niches. Don't be embarrassed by starting small. Tiny. Microscopic. Don't be ashamed if you're starting out with a blog that gets three views, two of which are you refreshing the page.
Incumbent advantage is overrated. Most of them are just bloated, slow, and coasting on inertia. Big deal.
Stay away from partnerships.
The punch to the face happens when you realize you build a product nobody wants. It will happen to you. Acknowledge it. Move on.
Design rules. Trying to build a product without a designer is like explaining Netflix to your grandma over the phone.
Great software is simply knowing how to not confuse people. Navigation, interaction and copywriting. The best are technically savvy enough to visualize those components in high resolution.