Yes, what direction does it face and how many hours of sun does it get in the growing season?
Be careful with planting any trees, unless you just want to have a shade garden (which can be beautiful).
Think about what you would like to do in your little patch of back yard. Do you have some outdoor sitting space? Outdoor eating space? If not I might take out the raised beds on the left side of the picture and use that for table and chairs, gazebo or something like that. It will give you a nice view looking down into the garden below.
Quick way to get pretty privacy is put up fencing and grow vines up it.
I would put a little pond or at least a fountain, bird bath, some kind of water feature, in the center. Path around the water feature and around the perimeter. The rest can be beds, either formal in geometric designs with borders or looser curves without formal borders for a more casual look. You have a little box, so you definitely want some curves in there, whether that is circular beds, or looser curves, more kidney bean shaped or whatever. Grow herbs, veggies, flowers, preferably mixed together.
Look for inspiration pictures
To keep it from being boring, think asymmetrical. Note how the fireplace in second picture is on the diagonal.
I'd want a little more going on than this. Think about that pond / water feature in the middle of the path with the path going around it on both sides.
I like gardens and greenery. But for low maintenance, the contemporary thing is to pave over much of the space (with paver tiles, flagstones, decking, etc):