I am trying to stabilize laser frequency with PID controller.

[pallab]

I am trying to stabilize the laser by locking it to a transition peak with the help of the PID controller. On the controller frequency response plot if I change any parameter of the P,I or D the amplitude or phase response changes. I do not know how to read the graph of the transfer function for deciding the best value of the PID parameter for the system, from the response curve. I do not want to tune the PID controller by trial and error methde. I am not from control theory background. I am struggling, trying to get some information from online but not able to make progress. I want to know what I should look on the curve, how should be the shape of the curve for tuning the controller.