When you're balancing the object on your head, you'll see water drops fall and hit frequently on the object and on the head of your character. Most of the time, they won't do a thing; if they fall and hit straight down on the object or on your head, they won't change the movement of the object. If they strike a glancing blow, though, then the object will move slightly, so you'll have to compensate accordingly.

Bombs will also fall occasionally on the head of your character. These cause a lot more movement due to their explosions, even if they fall and hit straight down instead of to the side. Watch closely when you first see them fall to see ho they affect the object that they hit; then use that knowledge to predict and counteract their effects on future falls.

You can earn coins, and coins can buy you new hats/objects to balance on your head. If you want to get more coins quickly, then go to the hat select screen and scroll over to the coins +10 icon. Center it, and a video icon will pop up; tap that icon and watch the video, and when the video finishes, you will earn 10 coins. Repeat as many times as you want to for all kinds of free coins.

When you're in the hat select screen, select the random hat icon and you can play with any hat in the game, even the ones that you didn't buy. Use this for a new challenge every time and to preview hats before you buy them; the hats will be randomly selected, though, so you'll have to keep trying before you get to the one that you eventually want.

Most of the hats perform very similarly and contribute evenly to your score. Smaller hats tend to make for smaller targets for the water drops and the bombs, making them a little bit easier to balance; larger objects, such as the birdcage (which costs 70 coins), tend to be a little bit more difficult to balance.