The trickiest part of awarding treasure is determining what magic items to give out. Tailor these items to your party of characters. Remember that these are supposed to be items that excite the characters, items they want to use rather than sell or disenchant. If none of the characters in your 6th-level party uses a longbow, don’t put a 10th-level longbow in your dungeon as treasure.
A great way to make sure you give players magic items they’ll be excited about is to ask them for wish lists. At the start of each level, have each player write down a list of three to five items that they are intrigued by that are no more than four levels above their own level. You can choose treasure from those lists (making sure to place an item from a different character’s list each time), crossing the items off as the characters find them. If characters don’t find things on their lists, they can purchase or enchant them when they reach sufficient level.