Force Sensitive Resistor (FSR) is a sensor which lowers its resistance when there is force upon it. If there is no force acting on it, the resistance is ~10MOhms.
1- Simple Voltage Divider
Cons: ADC impedance introduces distortions in measurements
Note that there is a limit on the current flowing through FSRs. The circuit should also take that into account.
1- Are there any other circuits for this application?
2- What is the best configuration for (A) Calibration and (B) Normal Use?
Here are my other questions related to FSRs:
What is meant by "adjustment of the output gain and offset" of a Force Sensitive Resistor interface circuitry?
What is the maximum force that a FSR sensor can detect?
FSR sensors have both creep and hysteresis. That is one issue. The other issue is a good interface circuit which both limits the current and produces zeros offset and noise.