I would start by painting your door (if the subdivision allows this). Flowers would also add curb appeal along the driveway. If that's too much then large urns with flowers would look great on both sides of your garage.

If you can add a trellis on the yard side of the sidewalk, perhaps 6' long, with a post at each end, iintegrated into a planter box, perhaps 3' H x 2' W x 6' L, that will provide you with a definition of entry without attaching it to the home. Verify that this is permissable with CIty and HOA prior to implementing. Here is an idea for the trellis part of it. I hope that this helps out.

We would need to see the entire subdivision covenants in order to suggest anything useful.