I think that a pergola in the area where the grill is located would be a nice start. I'm sure you could find some how-to instructions so you could build one yourself as they can be a little expensive. This would create a garden room where you could have a seating area. You could also create a garden path from the garden room into the grass area using pavers. Put some flowers along the side of the garage and fence line to brighten up the yard.

Good luck and have fun with it - that space has lots of potential!

Diana