"This tool does exactly one thing well, and uses no extra permissions/libraries/network access to get there."

I also put a lot of value on a well designed CLI. A GUI should not be required for anything.

Show value in as little steps as possible.

If it needs access to my real system data, tell me why, and guide me through the all steps I need to complete to set it up.

Write out every step. Make it obvious. Come back to your instructions the next day and make them simpler, and more obvious.

Have as few steps as possible.

Time to value is key here.

portable app, no internet required, is what gets me onboard.