On the top of the tarp, select the edges shown in red. Chamfer the edges by about 0.1 or so. This will for a very thin line of polys. Select the thin strip of polys and extrude it inwards a small distance, say about -0.1. That completes the tarp.
The tarp is held on the car by a series of bolts so we must make those now. These are easily made with a spline. Draw the shape shown and lathe it to get the bolt.
Now simply place the bolts all around the tarp at the positions shown.
The door handle is extremely simple to make and I'm sure you would feel insulted if I went through it step by step!! All you have to do is start with a spline, make it renderable, convert it to a poly and then adjust vertices to shape it.
Next is the door latch, start with a box like the one shown.