There are a few ways that you can flatten land after tilling. One way is to use a roller. You can either buy or rent one. If you have a lot of ground to cover, it might be worth buying one. Another way is to use a tractor with weighted tires. This will help press the soil down and make it flatter. Finally, if you don’t have access to either of those things, you can always go over the ground with a heavy metal object like an anvil or even just your car!