Practice your steering
You'll be doing a lot of steering in Marble It Up: Mayhem! so it's definitely a good idea to get acquainted with it. You won't be able to turn quickly on a dime so it's important to get used to steering timing. Turns in this game feel heavy at times, sort of like in car games.
Your best bet is to avoid turning too late as this could easily lead you into falling off the map or bumping into something. It's important to keep your pace up, and by mastering the steering of your marble, you'll be able to keep a steady speed.
Most levels are about reaching the goal within a certain time limit, so good turning can lead to success.
Get comfortable with the camera
The camera angles in the game are tricky to handle initially, so it's a get idea to get familiar with it. This is because you need to turn your camera in the direction your ball is going in order to see where you're going. Of course, if you are able to go through a level with the camera in just one position, then, by all means, go ahead and challenge yourself.
But, if you don't want to do such a thing, then definitely get comfy with camera control. You'll be grateful once you do. It's essentially like doing double duty because you have to worry about both steering your marble and the camera at the same time.
One good way to practice is by heading back to the earliest levels. These are simple and are excellent to practice on all of your moves.
Time your jumps as best you can
One thing about Marble It Up is that it can get sneaky on you at times. Each track is pretty unpredictable soo don't be surprised if you don't get the best score after one go. One of the pesky things they throw at you are the holes and gaps that make their presence known on certain levels.
Obviously, because of this, it's highly important to use the jump button that should be on the right side of your screen in-game. Timing is key on these jumps and it's to slip up and fall. And although you respawn after falling, it takes away precious time.
And on several occasions, you'll see consecutive gaps and/or holes so you'll be required to make some quick hops. Clearing jumps can be a huge help when trying to earn the highest medal. As long as you don't have many hiccups after dealing with the holes, you'll be on your way to a good score.
Watch your speed at times
Speed control also plays a role in achieving success in Marble It Up. It's easy to go full speed ahead as you zoom through the track like the speed demon that you are. But, that doesn't mean slowing down is a bad thing. In fact, it can help you hit those sneaky turns and jumps.
Also, there are many times where you have to hop on platforms and by slowing your speed down a little bit, you'll be jumping on them with ease. If you come in too hot, you'll likely mistime your jumps causing you to ricochet off of the platform.
Don't get me wrong, it's good to go as fast as you can, but don't hesitate the need to slow your pace briefly to help you with turns and jumps. Falling off a map by going to fast or bouncing off a platform will take a good chunk of time off so it doesn't hurt to play it safe when needed.