Know Your Birds
Each type of bird has its own strengths and weaknesses. Knowing which bird to use in given situation will greatly improve your chances of beating the level. For example, the little blue birds perform best against glass, especially when you split the bird into three just before impact. Yellow birds can splinter wood with ease, but you'll need black bomb birds to take out stone barriers. Save the white egg-dropping birds to attack pigs in hard-to-reach places.
Scouting
If you pinch and zoom on your mobile device, you can scan the entire battlefield to get a better grasp of the distances and angles involved. Also, pay attention to the dust trails each bird leaves as it sails through the air. These trails will help you aim your next shot, letting you follow the same trajectory or adjust the bird's flight higher or lower.
Structure Strategy
Before launching birds, make certain you study the structure for any weak points. Look for hollow wood boxes or spindly support poles. You always want to take out the foundation first, causing the top levels to crumble. Try and target support beams. Striking these beams can bring the entire structure to the ground.
Attack from Above
If the direct approach doesn't work, try attacking the structure from above. Launching high, arcing shots can be an effective way to exploit potential weaknesses. The ploy works best with blue birds, which split and rain down destruction, or yellow birds, which can accelerate and arrive with explosive momentum.
Rolling
You don't always have to fire your birds through the air. Flinging them along the ground and causing them to roll into the target can be an effective strategy for cracking foundations or smashing loose debris for extra damage points. Don't shoot the birds directly onto the ground. Imagine you're skipping a rock. Yellow birds roll best, with their ability to accelerate their roll speed.
Bomb Birds
The black bomb birds can be incredibly destructive, particularly on stone structures. To get the most out of each bomb bird, try and land them into corner areas where they can explode and take out as many adjacent blocks as possible. If the level features a box of TNT, try to hit it with your bomb bird to trigger a explosion.