So you followed the learn startup principles and scrappily validated why your product might succeed. You invest time, financial and social capital into gathering resources to execute, and will eventually find out if it gets any traction a few cycles after launch.
This can be wasteful and slow. The inherent biases in this approach can be very difficult to self-detect.
A good way to counter this is to consider that your startup has already failed - before you've built anything. Employ Null Hypothesis. Use minimal resources to understand why your product might fail and prove or have a rational understanding as to why it wont.
There is a strong shift in thinking if you take this route - biases are checked. Causal reasoning turns into Effectuation. You're no longer gambling your time away on biases; but actively guided by considered decision making designed to protect against failure.