Here is what works on mine.
For the sides, I fold in the back flap first after unzipping, like so:
Then I roll up that back corner, and then the front part by the window.
Then inside I always make sure my back strap is as tight at is can be, and I may even overdo it, you can see the plastic hoop where it is attaching is kind of being bent up:
And then I also make sure the top straps on the inside are always as tight as they can be (mine go to just about the limit):
This seems to keep the top fabric pulled taught against the snaps on the windshield frame and the whole thing the smooth look. I also just generally roll up the back rather than un-attaching it, and leave the bar in snapped in to the back holders.
Let me know if that does or doesn't help any and we can figure out what's up.