Aim for the lower half
If you've ever stacked blocks, cups, or other objects and thrown things at the stack, you may be familiar with this strategy. The bottom part of the stacks are usually the widest to work with. They also are the foundation of the towers, of course, and what better way to bring it down? By tearing up the foundation.
Now don't get me wrong. this won't knock down the entire tower in one shot, but you can get a chunk of them to fall. Think of it like a sweep under the legs in a fighting game. It will knock them down, but it won't necessarily finish them.
The same applies here. Go for the legs, get the upper side of the tower to crumble, and then finish it off. There's almost always going to be a few still laying around on the table. And you do need to knock them off, they can't just fall and lay there. So go ahead and grab the broom and start sweeping them.
Pay attention to how many balls you have
OK so on most levels, you have a limited amount of shots to work with. Some may give you five, while others may give you a lot more like 40 or 50. It kind of depends on what kind of tower(s) you're dealing with. Sometimes, if there are multiple that you need to destroy, then you'll receive more.
However, if it's a single one, then you may be limited. So the idea is take your time with shots. Unfortunately, you can't go all Rambo and fire like crazy. So just take your time, and plan your next shot. Because remember, even after making the blocks fall, you will have leftovers.
So, if you only have something like five or six balls to use, then make at least two of those shots your best ones. So that way, you'll have a few left to wipe the table clean and move on to the next level. Just have a napkin ready for your cannon after it gets done feasting on the blocks.
Unlock some new canons
What's a good casual mobile game without some fun customization? There are several different styles you can unlock, just by progressing through the game. From penguin to bear cannons, there are quite a few to earn. No, these do not possess any kind of magical powers.
It's all about style. And sometimes in games, even the smallest customizations can be appreciated. You'd be surprised how much a new look can help make your experience better. Just having a fresh change can sometimes make it feel like you're playing a slightly different game.
It's sort of like playing golf. Changing the grip on the golf club makes it seem as if you have a brand new club, although it's that same old dirty one that you had tucked away in the closet. Yes, I know, I'm diving too deep into it, but this is true for any game and it's nice for a simple game like Shooting Balls 3D. Now go get some new cannon swag.