I'd start by planting trees first. Although it might be better to wait until fall to plant either trees or shrubs, since we're just coming up on the hottest time of year. Make a plan for where you want your trees, and buy them in the fall when the weather cools off some.
Think about privacy, too. Do you want a large shrub out front to screen the windows facing the street, or for noise abatement? At the sides to separate your yard from the neighbors?
For this summer, I'd be content with some big planters (containers) on the front porch, and make an overall plan for the yard, being sure to know how big the big feature plants will get before you go for it. Then spend your time getting compost from wherever you can lay hands on it. Your County landfill might be your best source.
