Accolades are tasks given by the game, and, while it doesn't are needed to a 100% file, some players like to have then, as some of then give XP boosts. Here is the list:
In the final area of Minefield Mishap, you are supposed to carefully walk through a maze of mines to reach a golden staff. This entire maze can be skipped. After taking the last teleporter, you see the staff item on your characters right. You need to collect this in order to complete the challenge. If you walk directly towards the staff and into the first mine on your characters right, you can push and walk through the gap before the mine replaces itself. You'll get knocked back and take damage, but the mine wall wont replace the detonated mine before you walk through again. This is especially easy for characters with a dash move.
Some Skylanders have difficulties do finish the Double Trouble's Heroic Challenge (You Break It, You Buy It!), but there's a way to help.You need any Location Piece (2 will help more)/Anvil Rain, or the Time Twister Hourglass/Winged Boots, or booth. When you go to a place with hard-located enemies for certain Skylanders, use any Location Piece/Anvil Rain to defeat then without breaking anything. Use your Time Twister Hourglass/Winged Boots to gain time in empty sections.
In the Wii version, use your Legendary Treasure Chest Magic Item in The Ruins. Collect the treasure, then talk to any character. After talking, come back to the place of the Treasure Chest, and collect the treasure again. You can make that infinitely.