The Donkey Kong Country: Tropical Freeze Walkthrough reveals the location of every KONG Letter and Puzzle Piece in the game.  Can't find one? 
6-4 Blurry Flurry - Donkey Kong Country Tropical Freeze Guide - IGN
Donkey Kong Country: Tropical Freeze Review (Wii U)
6-1 Homecoming Hijinxs - Donkey Kong Country Tropical Freeze Guide - IGN
Donkey Kong Country: Tropical Freeze Guide - Collectibles: Stage 7-1
1-A Zip Line Shrine - Donkey Kong Country Tropical Freeze Guide - IGN
4-B Shoal Atoll - Donkey Kong Country: Tropical Freeze Walkthrough - Neoseeker
3-5 Twilight Terror - Donkey Kong Country Tropical Freeze Guide - IGN
2-B Rodent Ruckus - Donkey Kong Country Tropical Freeze Guide - IGN
2-A Crumble Cavern - Donkey Kong Country Tropical Freeze Guide - IGN
4-B Shoal Atoll - Donkey Kong Country Tropical Freeze Guide - IGN