My current White Rodgers thermostat stopped working.I bought new Honeywell RTH6300B thermostat but forgot to label the current wire connection. Can anyone guide me now on choosing which color wire should be connected to which thermostat terminals.

I have 4 wires available to be connected to thermostat
Red
Blue
Green
White

Thanks,
Pankaj

They should connect to the corresponding letters except for the blue and you have no yellow, so we can guess they substituted blue for yellow. Good luck , Mike
White to "W"
Red to "R"
Green to "G"
Yellow to "Y"
A jumper between "RH" and "RC" with the red wire.