As Paul suggests, keep it simple to begin with. Try this
int sensor = 2; // Analog in
int val =0; // Current reading for analog pin
void setup() {
Serial.begin(9600);
pinMode(sensor, INPUT);
}
void loop() {
val = analogRead(sensor);
Serial.println(val);
delay(100);
}
It is basically your program with the stuff that is irrelevant at the moment taken out and a pinMode() command for the sensor, which was missing, added in. What sort of output do you get under different conditions ?