If you're looking to cut perfect lines with a zero turn mower, there are a few things you need to keep in mind. First, you need to make sure that the blade is sharp and in good condition. A dull blade will not cut as cleanly or as precisely as a sharp one. Second, you need to ensure that the mower deck is level and even. An uneven deck can cause the mower to veer off course, resulting in imperfect cuts. Finally, you need to take your time when cutting. Rushing through the job will likely lead to less than stellar results. If you follow these tips, you should be able to achieve clean, straight cuts with your zero turn mower.