The vinyl wrap will ideally need a shiney, smoothed surface to adhere to. It's best to sand, prep & paint first then apply the wrap.
With wrapping anything, its best to pull the vinyl tort over whatever your wrapping.
Try not to apply to much heat and stretch the vinyl to much as past a certain tolerance it will not return to its original form.
Pull it tort, heat and press the vinyl into the gaps, let the vinyl cool, cut (not right up to the edge or near the corners), leaving a load of overlap for now, pull tort around the shape while applying heat and hold in place, let cool and trim a little at a time. If not too much heat is applied you should not get any "shrink back". When your happy, trim the rest nice and close to the edges and et voila Robert's your day's brother!!
EDIT: leave a decent overlap on the inside where the vents are due to heat from the vents as this may cause the wrap to lose its shape and shrink back.
Vinyl can be reheated (which will allow it to shrink back to its original shape), reapplied and is pretty strong stuff so no need to be delicate. I have done loads of stuff and am still fluffing it up but reapply and carry on.
As I said, its 90% prep. The more time you take with prep the more OEM and less like an non pro job.
Hope this helps.
and yes TAKE YOUR TIME, all told this took me a couple of days on and off.
Mine...
Sanded...
Prepped....
Wrapped....