Hi there!
I’m two years in as a cofounder. We have one full time employee beyond me and my business partner. We raised under a million in a pre seed round.
Prepare for what will feel like whiplash when it comes to the product. At this stage, you’re trying to find product market fit within the market you’ve chosen. The idea the founders pitched to you and their investors is likely not where you’ll end up, and that’s ok! Just don’t misinterpret agility for stupidity or lack of vision. Running a business is really hard, and getting other people to buy what you are selling will be wavy and confusing.
As an engineer, invest in things that speed up your process. If you deploy often, make sure your deployment process is optimized. If you need hyper reliable software, spend time investing in testability, test documentation, etc.
Spend a lot of time mentally preparing that what you build will get thrown away, but that’s not a bad thing.
Realize that productivity is cyclical, and you when you’re most productive, block off your time. When you’re less productive, try to tackle low hanging fruit or bang out small tasks that are nagging you or your customers.
Get a therapist if you find yourself stressed or anxious. Talk therapy can help you stay on track.
You’ll likely work a lot of nights and weekends, but carve out time for yourself when you can.
Thank any significant others for giving you the space you need to be productive.
Add a hobby that will force you not to work for an hour each day (we added an 8 week old lab puppy I’ve been training for the last year).
Get sufficient sleep every night.
Realize you’ll disagree with decisions that are made, but learn how to trust those around you when they’ve been empowered to make a decision. It’s ok if they’re wrong, and it’s ok if you would have been right. You’ll make mistakes to, and that’s just part of life.
I could honestly keep going for an hour :) starting a startup is really hard!