Here is a good checklist of what to think about when designing for the web. Some highlights:
- Assume that people won’t read the instructions.
- Redundancy is a useful design technique. Labels+icons, color+width, etc.
- Use loading indicators for XHR requests, even if they’re likely to be very fast. You never know how slow or broken it might be for a user. They should know if something is missing.
- Don’t give someone 20 equally interesting things to do right off the bat. Give them a more focused presentation upfront before turning them loose.
- Get live data into your visualization early. If you can’t, use historical data or something else a little bit representative. Visualizing random test data will lead you astray.
- Clean and transform your raw data stepwise. Make it a repeatable process. Use Makefiles or shell scripts if you can.
- Assume your page will be one of user’s dozen open tabs. Use short, descriptive page titles and a favicon.
- Have a recovery plan, and test it.