Some tricks of the trade are setting anchors as close to the ground as possible. Use padding and avoid friction wherever possible. Favor decent sized pulleys over carabineers for change of direction or as the traveling pulley. A good rule of thumb is the pulley needs to avoid bending the rope in a loop less than a 4:1 turning radius. A 2" pulley is perfect for a 3/8" hauling line. Adding an extra pulley to avoid running the rope over a shelf edge of rock is always a wise precaution. Anchors fail sometimes, often due to shifting loads. Try to predict where projectiles will fly and take precautions. Always wear your safety gear.
When setting a two anchor point system, remember how a vector pull works. That real skinny person can easily topple two really big persons when the line is taught (180o) by pulling in the middle of the rope. Reduce the angle to 45o and you have an even match. Try to make the angle of pull on the anchors 90o or less.
Beware of rubbing any of your soft lines over a hard surface like a rock. The rock will act like sandpaper and eventually wear out the line (or worse yet - cut it). When confronted with this challenge, try padding with some clothing or better yet, add an extra pulley to avoid this contact. A more subtle example is a carabineer with somewhat sharp edges. A major advantage of a pulley over a carabineer is greatly reduced friction. Friction not only causes wear, it can add a great deal of heat and this can be a real concern with Polypropylene line which has a low melting point.
Here is a nice video on padding anchors and how to select good anchor points: Padding Anchors.