This guide assumes archers, barbarians, goblins, giants and wall breakers are level 5.

Target: Collector - Level 11
Defending Buildings: level 9 cannon or level 8 archer tower (nothing else both)
Attack with 2 barbarians and 2 goblins
100 Seconds of training time used and 4 troops space
Note: Make sure the cannon targets the 2 barbarians first. You will have 0.2 seconds to get all your troops deployed and to the collector. If its just a cannon use a minion.
Status: Not Tested

Target: Collector - Level 11
Defending Buildings: level 9 cannon and level 8 archer tower and a level 5 mortar
Attack with attack with 4 barbarians and 2 goblins
Time: 140 Seconds
Note: Deploy Barbarians on closer side to the defenses.
Status: Tested

Target: Wizard Tower - Level 6 - Behind Level 6 Walls
Defending Buildings: Wizard Tower, Level 9 Cannon, Level 8 Archer Tower
Note: Wizard Tower is directly accessible but all archers must be clumped up. Giant and Archers are seperate splash groups. Make sure giant tanks all damage until it dies
Attack with: 1 Giant and 8 archers.
Time: 320 Seconds
This will kill the wizard tower and leave you with 5 archers that have full health.
Status: Not Tested

I will expand on this guide but if you guys could help that would be much appreciated. If you found a troop combo that destroys something with less training time or less elixir I would be glad to add it into my little guide.