A landscape covered with crushed stone doesn't require much maintenance other than raking once or twice a year. Esthetically it doesn't add much to the attractiveness of the lot though. Putting a lawn in is a step in the right direction. Adding plants and trees is even better. Plan your landscaping before buying a single plant or spending a single dollar. Consider where and how you live and you'll be pleased with your final landscaping.
Draw a sketch of your yard to scale. Note any shady areas from buildings, neighbors fencing or walls. Add in the plants and trees currently in the yard.
Decide how you are going to use your yard. If you entertain a lot then a patio and grill area would be important. If you have children, a grassy area and sandbox might be your choice. Look at privacy problems. Block out unsightly view with plants or trees. Use trees to stop neighbors from looking directly in your backyard.
Add the plants and trees to your sketch and shopping list.
Select plants that do well in your USDA hardiness zone and climate. You may love orange trees but they won't grow in hardiness zones below nine. Similarly certain trees like apples need a period of chilling during the winter to blossom and set fruit. If you live in Southern California, apple trees won't thrive.
Choose plants that like shade for the shady areas and plants that like sun for the sunny areas. Most trees require direct sunlight but there are a few that will grow in dappled shade, like Texas Laurel.
Check the height requirements of your landscaping plan and match them with the growth habits of the plants you're considering. If you want shade for example: Choose trees that have an umbrella shape and don't grow too tall. Ficus trees, the outdoor variety, grow to 60 feet wide with a 60 foot spread. They are good shade trees for a landscape that is comprised of several acres but will overpower a smaller yard.
Examine the exact variety of plant at the nursery. Some plants within the same family have very different growth patterns. Grass is a good example. It's used for lawn, but it's also used as ornamental plants in the garden growing from 6-inches high to over 10 feet high. The grasses at the plant nursery are all about the same size in their containers. In other words the 1-gallon purple fountain grass which grows to 4 feet is about the same size as the 1-gallon blue fescue grass which grows to 12 inches.
Amend the soil before planting. Dig the soil to a depth of 24 inches. Add compost and organic material. If the soil is clay add gypsum and sand as well as compost and organic material. Exactly how much depends on your soil. Once the plant is in the ground it's difficult to make up for poor soil by adding fertilizer or mulch.