Ok so I have no idea what I'm doing... I don't know how to find new people, I don't know what to do about what i found at the crime scene.. and how often do new hints pop up?? I'm supposed to meet some girl after 6 but when is that? Any help will be greatly appreciated!
In order to make time pass in a feature mystery you need make the story move by asking townies/suspects questions that you haven't asked previously, checking research and on occasion factions. Just check every inch of town and see if there might not happen to be some interview options that you haven't explored yet, and then just follow the leads they give you :)
Feature mysteries work a little different than regular mysteries, and what you find at the crime scene won't always be something you can check with the townies the way you usually can, but when/if it's possible the option to enquire them about the evidence you found will show up, but might not be there to start with.
New hints will pop up either by talking to the suspects, the townspeople (who'll also have a lot more information than usual), from research or cutscenes. Just explore every inch of town (but of course be careful that your suspects don't clam up on you), and if you get stuck the best way to get unstuck is usually to take a tour of town and see if new interview options have become available :)