Erosion is caused by unstable soil and particles that are easy to pick up. To increase soil stability, one can choose to plant vegetation like grass or a cover crop, or even physically cover the ground with material like a tarp, fabric, or mulch. There are also spray-applications meant to control erosion and protect loose soil.
In places where this isn’t possible, it may be necessary to redirect incoming water with barriers such as sand or gravel bags. Placing barriers above and around your site will work best when placed uphill. Water will run downhill regardless of how gentle the slope may seem. You’ll want to prevent water from running over your soil and disturbing loose particles, and should place your barriers accordingly.