Don't forget that your awning can sometimes help as well if it can be set up to effectively shade one side.
Remember too that cold air drops like a rock, so heavy in-and-out traffic will hurt. Try standing outside the door, fold up the stairs momentarily so you can get close, then open that door - it's amazing.
I also discovered that part of my basement area was cooler then I would expect. Cold air was dropping down through a hole into the basement. Sealing that hole helped a lot. Look low inside for any significant signs of leakage.