Five-starring the campaign really isn't as hard as it seems as long as you follow these tips:
- Max out the crowd meter by doing perfect actions (whether it'd be changing discs, swapping, muting, soloing, etc.) and keep it full by the end of the timed goals so you can get the Crowd Bonus of 1,600 points. Also, it helps to fill your crowd meter as soon as you receive your first timed set of goals. Keeping in mind the crowd meter depletes after a few seconds, you need to stay active.
- The requests play a big part in getting a high score. The trick is to know and remember what songs you put in your crate, don't use auto-fill for your crate. What I did was use a whole bunch of songs of two different genres to make it easier to fulfill requests. You'll usually get requests on longer timed goal sets, so it's best to prepare. (EDIT: Thanks to TonySki, be sure to get two requests done at the same time, this will help greatly)
- The goals aren't random, they're the same. So, if you're having trouble five-starring a set, it's best to remember what to do for the next time.
- The goals with no time limits are perfect times to catch your breath and take all the time you need, for there isn't the crowd meter either.
- EDIT: Enabling the No-Fail option only gets you the "Good" Crowd Bonus (400 points) even if your crowd meter gets full and is therefore NOT RECOMMENDED.
- EDIT 2: Another helpful tip, thanks to danpsfx, is slowing down the tempo when it's not required for a goal. You could go the bare minimum (90 BPM), if you'd prefer.
So in short, don't use No-Fail, keep your crowd meter maxed out, be prepared for requests, stay active, and most importantly, DON'T GIVE UP!
I hope this guide helps.