Two main learnings from working as an engineer in three different product startups for about 4.5 years in crypto before joining Wormhole, that I tell to any builders I am talking to are:
1. If you're not embarrassed by the first version of your product, you've launched too late (Reid Hoffman)
2. Don't overengineer the backend without spending enough time on the UI. Ideally have a full-time UI/UX engineer/designer in the team as quickly as possible, who is only focusing on user experience.

tldr: Feedback from the right users is everything.