Yes indeed, blank slate! To start with you mentioned "a flower bed along the front of the house," but it is a teeny little strip of teeny little flowers. A very common mistake of landscapers. Yours is barely visible and all out of scale with the house. What you want in a foundation planting bed like that is a wide bed, that has a curving edge. Your house is a rectangular box, you really want to break that up with some curves. So a curving edge, wide enough to have some groupings of plants, not just a straight line, and some bigger plants, like shrubbery and even small trees.
Here's one sample of what I am talking about:
https://img2-3.timeinc.net/toh/i/g/12/ya ... plants.jpg
Note how the height slopes down from tall shrubbery closer to the house to smallest things in front.
The back yard looks like no one ever sets foot out there. Think about what you would like to DO out there. Do you have kids? Then you would want a kids play area. Water features always make a space more pleasant and attractive, at the minimum a bird bath, better would be a bird bath AND a little ready made pond (you can buy them cheap these days at Home Depot type places). Fire pit is nice. Table for eating, at least a picnic table. Grill. Some kind of covered out door space for sitting, like a gazebo. A couple little veggie gardens. A shed for your lawn mower and garden tools? I couldn't tell if you have a patio in the back? Some hedge along the back for a little sense of privacy, enclosure.
Start by mapping it out on paper, what things you want where in the back. Then put in curving walk ways to those different things.
https://www.elraziq.com/wp-content/uploa ... -ideas.jpg
Yes, your backyard could look something like that. If you weren't going to invest a fortune in making it happen overnight like they do on TV, it would be a DIY project for the next few years.
Do look around for inspiration pictures of your own. I think they are very helpful to give you ideas and a sense of what you are aiming for.
For any more details, it would help to know where you are located and what direction the front door faces.