[robbick]

You are right to be concerned - so many side projects don't gain traction due to simple UI issues putting users off.

1. As other comments have mentioned - if you are willing to pay, a good designer will go a long way.

2. Use a common component library with a custom theme so it is good code but not 100% the same as elsewhere

3. Keep lots of whitespace between everything

4. Keep it simple - good UX is about so much more than UI and feature creep is so often the enemy of good UX