Serial.println not outputting
The answer to no ouput, and suspecting your data source is to replace the data source with a constant value or a string until you get that problem sorted, and then go back to your data source and debug that if necessary.

That said, I don't see any issue with you trying to print the output of an analog read. Obviously you should get something, even if it's just a single zero on each line, twice a second.


Is your monitor the Arduino built-in monitor?
Is it set to 9600 baud, as you've set your output rate in the program?
Is there anything else connected to the Tx pin, Pin-1 (Arduino numbering, not chip numbering)?
There were no error messages from the compiler or loader, right? (The libraries, bless-'em, always get a few warnings; unfortunately we have to ignore those).
You've no reason to believe the Arduino is other than 100% good?