(1) You arrive in the Dragonbone Wastes to a full moon and an empty landscape. Nothing is around at the entrance. That will soon change.
(2) Up the path, a disciple battles a group of childer hatchlings. Let the two sides damage each other for a few seconds before you approach too close. Hit the largest group with a powerful AoE to thin the numbers before engaging in melee to crush the rest.
(3) Slice through a second group of childer hatchlings to reach the pile of bones along the right side of the slight hill. Slip into the new Fadewalker boots found in the bones, which are likely an upgrade for one of your party members.
(4) A stretch of short canyons wrinkles the land over the slight hill. Genlocks lie in ambush on either side, including two genlock emissaries and an armored ogre. Inch up and pick off the normal genlocks with single-target ranged attacks. When you spot a genlock emissary or the armored ogre, cast a powerful AoE on the unsuspecting darkspawn (Inferno or Blizzard work great). Hold your ground and let the AoE damage hurt or kill your target. Anything that charges out of the AoE at you will be weakened and an easier foe for your melee DPSers.
(5) Head south to the gate leading into the Drake's Fall courtyard. Childer hatchlings attack hurlocks in a chaotic sea of limbs and froth. Wait for the childer hatchlings to defeat the hurlocks and then face off against them at the gate. Only after the childer hatchlings are dead, and you've healed back up to full, should you enter the courtyard.
(6) Setting foot in the courtyard summons a high dragon. You can't enter Drake's Fall until you beat the dragon. Fan your party out so the dragon's AoE breath attack can't hit more than a single party member.
Send in the tank to hold the dragon's attention. The healer concentrates all healing on the tank, unless the dragon catches another party member unaware.
Use whatever tricks you have at your disposal: Force Field to protect a wounded ally, Time Spiral to double-cast spells such as Inferno or Group Heal, poison on your weapons, etc.
You'll go through quite a few stamina draughts, lyrium potions, and health poultices before you're through. When you're ready to enter Drake's Fall, search the pile of bones near the door for the Quicksilver helmet.