There are four types of rarity levels for all items:
Normal - white
Magic - blue
Rare - yellow
Unique - red/orange
How quickly you get this achievement is based on a little luck and how diligently you save your rare items (you probably won't have any uniques unless you've been playing for awhile). As you're out slaying various monsters, they will drop a wide variety of loot. In each town area, you will find a treasure chest labeled "Stash" that acts as your personal bank. This is where you will want to keep your rare (yellow) items until you have all the ones you need. Personally, I got this achievement near the start of act 2 when I was level 18.
For this acheivement you will need to own and have equipped at the same time:
- 1 rare or unique helemet
- 1 rare or unique chest piece
- 1 rare or unique boots
- 1 rare or unique gloves
- 1 rare or unique amulet
- 2 rare or unique rings
AND
- 2 rare or unique one handed weapons
OR
- 1 rare or unique one handed weapon
- 1 rare or unique shield
OR
- 1 rare or unique two handed weapon
- (there are reports of this not working: credit to
Springerr)
If you are having difficulty getting one or more of the items from monsters or need the achievement faster, there are several other methods to obtain rare items:
- use an Orb of Chance to change an item to a new random rarity level (not guaranteed to be rare or unique).
- use an Orb of Alchemy to upgrade a normal item to a rare item (guaranteed).
- use the player trade market to buy a rare item from someone else.
- trade with another player/friend in the same instance as you.
- buy a rare item from a vendor.
Note: the orbs are valuable and you may want to save them to use on higher level items later in the game. Additionally, you may not be able to afford anything on the trade market if you are still in your early hours of playing the game. As long as you aren't trying to rush, my recommendation is to just keep killing monsters and completing quests and everything will eventually drop.