the two crucial points you will need to be good at is the lip between the quarter panel and the lift gate. Get a heavy hammer and a 2X4. Take the tail light out. Beat that sucker over until the gap between the quarter and lift gate are the same on the left as it is on the right.
now when you do this its very likely where that crease is on the very out side, that will walk out. You will want to tap that in, but dont hit it so hard that you send that lip by the lift gate back in again.
Once the gap is good and that high spot is gone, the edge under the tail lamp is going to need to walk up where it once was. You want the metal to match right up to the tail lamp, just like it is on the other side.
You gotta walk the metal a good country mile to do this. A slide hammer with a hook to the back side is what you need. Its gonna take quite a bit of work I can assure you.
The closer you can get the metal to the original shape and contour the easier the job will be far better your final product will be.
Get the metal where you want it and post a picture here. If it looks good you can go to the body filler work as described in the thread above, if not I will help you as best I can to get it the rest of the way.
You CAN do this.