a) Shorten the length of leveling loops or routes as much as possible. Two instruments of the same class may also be used instead of forward and backward measurements to shorten observation time.
　　b) The measurement route, measurement season, and measuring instruments used should remain fixed.
　　c) Measurement operations should start from areas with large settlement and proceed successively toward areas with small settlement. When high-order leveling routes and low-order leveling routes are surveyed in the same year, they should preferably be carried out in the same period.
　　d) In areas with relatively large settlement, the measurement of one closed loop should be completed within a short time. When several teams work cooperatively on nodes in the settlement leveling network, they should conduct the connections simultaneously.
　　e) The optimal measurement period should be selected as the period with relatively minimal settlement, and the measurement should be completed in one pass.