Planters with bushes, packet of flower seed in an old tire with soil, cement statues, some plastic flower bed fence
Start plants from seeds, get cuttings from friends and neighbors, buy shrubs when on sale....
Also depends on if you're wanting to update the structure? Do you want to clear out old weeds, replace fencing, as some artsy type interest? You can add wind chimes, bird feeders, raised beds made from scrap Lumber, Lots you can do
Start your update by thinking if you need trees. They will be a bit pricey but they take a long time to grow so get them in the ground.
From there, start at the area you want to spend your time. Clean it up and define 1 garden bed to start. Plant perennials - they come up every year and many you can "harvest" seeds from to add to other locations.