I've started healing recently too, although as a Scholar, I always start to put extra attention to what people are doing once a wipe happens, when I notice someone doing something derpy like eating up every AoE there is there isn't much you can do. Being under geared seems to be also a frequent reason. If you see a tank pulls more than one pack of mobs or fray room joins your encounter (one example is one of the spots in Darkmor Darkhold [i'm sure i butchered this name hilariously but let it slide!] where 3 ice elementals spawn and a pack of dragons can come over from side room) you should be prepared to heal the tank exclusively till at least a few mobs fall off. A few times it happened when communication couldn't be established about doing the mechanics of the first boss encounter in Qarn 3 times and vote abandon not going through I just left and ate the penalty myself (stand on a glowing plate after the room-wide AoE applies Doom debuff to remove the debuff).