You need to equip fully enchanted weapon, armor and off-hand (bow). Fully enchanted means that the item should have 3 enchantment slots and they should all be upgraded to level 3.
You will start seeing items with 3 enchantment slots once you start playing in Adventure difficulty. As far as I can tell, Default difficulty does not spawn items of this kind. You can upgrade items by pressing Y on the item, pressing left/right to select the enchantment and then A to upgrade. Each upgrade requires enchantment points that you get for leveling up. Regular enchantment costs 1,2, and 3 respectively for a total of 6, while powerful enchantment costs 2,3 and 4 respectively for a total of 9 points to level up to 3.
What this means is that, you will need to level up 3 slots of 3 items to level 3. So, absolute minimum required enchantment points are 54, so you need to be at least level 55 to get this achievement. If powerful enchantments are included in the mix, you need more enchantment points. You can salvage items to get the points back, so do not be afraid to upgrade your equipments.
Edit: The enchantment in each of the slot may have to be unique and not same as the one in another slot. Thanks grrrrnade for this suggestion.