Unfortunately there's no easy way to get this trophy but here are some small tips:
Wave 1: Stay on the top platform and wait for the birds to come to you.
Wave 2: Again stay on the top and wait for them to come to you. You can kill one spawning enemy right away too.
Wave 3: This one relies somewhat on RNG. Immediately fly straight up at the start and hover there until the egg dropping monster comes under you and bop it. Then try your best to kill all the birds. I'd recommend the middle platform but some people say the bottom platform works well too. If you take too long the Pterodactyl will spawn and become a huge problem so don't dawdle.
Wave 4: Stay on the bottom platform and transform into Pegasus. You need to hit the bats while facing forward. If you die and spawn at the top then switch back to your bird form and take out the red knighted birds then concentrate on the bats. Again this one is somewhat RNG but as long as you know to use Pegasus and face toward the bats you shouldn't have too much trouble.
Apart from all that just keep practicing. It's honestly 50% luck and 50% skill and took me over 2 hours of retrying. Good luck.