Mow when there is sufficient light to see clearly. When using a walk-behind mower, mow across a slope rather than up and down. By mowing across a slope, you will be less likely to slip under the mower. Additionally, the mower can't roll back on you. Never mow a slope that is too steep for you to keep your balance or to control the machine.
Weed whips do an effective job on steep slopes.
Keep the mower flat, don't lift the front end over tall grass or weeds. Avoid mowing wet grass when you are more likely to slip or clog the mower. Riding mower operators should never carry passengers. Do not mow in reverse unless absolutely necessary. Never leave an unattended machine running.