It sounds like its beginning to gel, which is awesome, and John's examples are superb. How is the actual play going? The more you GM DW/AW the 'easier' it gets. Its not that different than what you would do GMing any other game, rather its explicit in the narrative as to when a hard or soft move is called for.
'Effects' are your special GM power. They can be mechanical or narrative, but as the esteemed Mr. Harper suggests, the fictional effects carry far more evocative 'weight' to the story. Its almost as if you have to convert a mechanical +1 or -1 into a fictional justification in order for it to 'make sense', whereas a narrated effect is so much more apparent to everyone and is deeply rooted in what is happening at the table.
Its all about being a fan of the PC's. In the introductions section to the AW chargen, Vx states that he could kill everyone just like that, but he won't, 'caus that would be a dick move.
In your example, the ogre could:
"You hear a bull-like bellow as a massive shape bursts from the shadows. The ogre's face, twisted in anger, is briefly illuminated by your torchlight. Then it brings a tree-sized club down at your head with a massive, two-handed swing, It crushes your skull for 20 damage".
You know that the PC has only 15hp and it will cause them to make the Death Move. Its a hard hard move (and possibly a dick move), but you can do that! Its a mechanical consequence that comes from the narration. Moves are both prescriptive and descriptive, it helps me enormously to remember this. Always include both facets to your conversation.
You could also say for instance: "You hear a bull-like bellow as a massive shape bursts from the shadows. The ogre's face, twisted in anger, is briefly illuminated by your torchlight. Then it brings a tree-sized club down at your head with a massive, two-handed swing. Luckily, your 'Thorin's Helm of infinite verisimilitude' protects your noggin, but shatters into metal and bone fragments, broken for ever, never to be re-forged."
Again a hard hard move. No real mechanical effect, but you are most certainly using up their most valuable magical resources, and possibly the mcguffin that the adventure was hinging on.
Please keep asking questions if you have them Rich! Its a great discussion we are having :)