Coverage & rank
Rewards are based on successfully completing 'beaconing-witnessing' cycles. Witnessing many other gateway's beacons proves good coverage and is rewarded each time. Rewards are then weighed (resized) based on your gateway's rank before being distributed to your wallet. Your gateway's rank should be equal to or above the network average to be eligible for the full reward. Your rank indicates your gateway's usefulness.
Place your gateway at an optimal distance from other gateways to maximize network coverage and increase your rank. Ensure they are not too close to each other to avoid redundant coverage overlap. This would decrease its rank.
Positioning & hardware
Best results are achieved if your gateway (antenna) has a 'clear line of sight' to other gateways and potential sensors. Higher is usually better; outside is better than inside; behind a window is better than behind a wall.
A high-quality setup returns higher rewards: use a quality LoRaWAN antenna that suits your location, use a short (low-loss) coax cable to connect your antenna to your gateway and use as little connectors in between as possible. Place your antenna as high up as possible.