As light as feasible. Fish tend to be annoying and bite when you are distracted or whizzing against a tree or some such.
For me it comes down to method used and the weather wind conditions, float and quivertip are my preferred methods, both with very light drag so there is indication well before the hook is set. It tends to vary, but in the initial stages the drag will be light enough so that the rod never fully loads.
The fish should be able to take line on the initial run, headshakes, rolls and changes of direction fairly easily. then slowly tighten a click or two. As the fish comes to the surface slack off the drag and use the rod's ability as others have said.
Remember to back the drag off completely after fishing to prevent the drag washers becoming compressed and ineffective.