Here's a HUGE tip. Don't worry about getting a single trophy until the final week. Just worry about getting the most valuable treasure. Then, on the final week, go for all the trophies you can get. When you reach the end where you're turning your trophies in, refresh the page and continue. You'll still be on the last week with the trophies you earned, and you can either earn the other trophies or simply go for the most money you can get.
Shooting the enemy castle with normal arrows gets you 10 gold. Destroying it makes it so no enemy archers can hide in it and shoot you. It also means enemy units can't use it as cover so you can shoot them the second they enter the screen. Stop saying there isn't any "bonus" for destroying it, because there clearly is!
 "Monster Slayers")
 "Great Game 1/5")
 "Ragdoll Avalanche 2")
 "MegaDrill")
 "Pixel Purge")
 "Bowmaster Prelude"){kind=icon}
 "Shore Siege!")
 "Ultimate Assassin 2")
 "Anika's Odyssey"){kind=icon}
 "Epic Battle Fantasy 3")
 "Dream World"){kind=icon}
 "This is the Only Level TOO")
 "Defend your Honor!")