If your yard is still uneven, string the line level along the 4 stakes and watch the bubble on the line level's panel. Record any high or low areas. Continue smoothing out the top soil with the rake or removing raised areas with the shovel until you reach even levels. Rake the area to spread the dirt around evenly and blend together the even, high, and low parts of your yard. After your area begins to look even, use the string level to measure the area. Continue raking until your level records an almost or fully even area. If you cannot completely level your yard using the rake, take a 2x4 board and tape a carpenter's level onto its top. Watch the reading on the carpenter's level—if the bubble dips to the right or left of the line markings, the ground is still uneven. Push the 2x4 board along the ground to lower any raised spots and fill the low spots with dirt. Check the level as you work so you can make the ground as even as possible.  Simple carpenter's levels can be purchased at most hardware or home improvement stores. Buy a 2x4 board that is approximately the same length as the area you are leveling. If you are leveling the whole yard, purchase a large 2x4 board and move it along the area you are leveling as you work. Alternatively, you could rent a water-filled lawn roller from a home improvement store to help you level your yard. If your yard is grassy and you did not have to remove any turf, then your work is done. If you did, however, then you will need to grow new grass from seedlings. Spread grass seeds over the areas you leveled, then cover them with peat moss to help the seeds retain moisture. Avoid stepping on your grass seedlings for the first few weeks to prevent trampling them underfoot.  Water your seeds daily to keep them moist, but avoid watering so much that puddles form. You could also mix grass seeds into a top dressing and spread 2 to 3 inches (5.1 to 7.6 cm) over thin or bare areas. Follow the guidelines on the package to use the right amount of seeds for the area you’re covering. New grass seeds need plenty of care and maintenance to keep healthy. If you stripped your entire lawn, lay sod on the ground and grow a new lawn. Roll out tight rows of sod over the bare ground, keeping the gaps between rows tight. Fill in the lines with soil or peat moss, then walk over the rows with a lawn roller to ensure contact between the sod roots and dirt.  Water your sod at least once a week, and mow the area whenever it grows taller than about 3.5 inches (8.9 cm).

Summary:
Use a line level to mark any remaining uneven areas. Use a rake to roughly level the bare areas of your yard. Use a 2x4 board to finish leveling the ground if it is bare. Grow new grass from seedlings if you only partially removed the grass. Grow new grass from sod if your lawn is bare.