I think I have found an ok way playing as a cruiser that works for me.
Try to follow either of these two tactics, find a BB how seems to know what he is doing and stick to him like glue. This is harder that it seems as many like to sail to the closet Island and corner camp the Island, or doing a dead stop in the middle of a gun duel.
If not supporting BB’s I go to the flank with fewest of my team’s ships and fight delaying action there. Doing this often consists of fighting an overwhelming enemy fleet. Do not get closer than 10 km of enemy ships, and try to dodge incoming fire.
PS, any active Squadrons out there who have spare room for a half decent +40 old cruiser captain?