Be Friendly
Are your friends also playing the game? Make sure that you invite them to join in the fun. If they like your music, you can enjoy better sales when you put out your hot new singles. Don't be shy about sharing your Star ID with the world, so you can find even more adoring fans. And finally, sign with a record label to increase the size of your audience yet again.
Don't Waste Energy
Before you participate in an event, make sure that you have full energy (indicated on-screen as thunder bolts). You can tap on your bolts to fill your star meter. When you can afford to, instead of taking small actions, utilize those moves that require the most energy, which will allow you to gain stars more quickly and lead to easier success. If you start an event without full energy or you fritter it away on smaller actions, you'll likely find that you've wasted your time, particularly in later events.
Look Around You
When you explore the various in-game environments, do so thoroughly. Often, you can tap on objects to find additional energy, money, or experience that will help your career. Whether outside or in buildings, make sure to investigate so you don't miss out on those easy rewards.