I have a couple that are really tough. What works great is to put your knee into it- literally. Lean over the ale pail, stick your knee hard in the middle, and then "peel" the lid up towards you on the far side. I hope that makes sense. If not let me know, and I'll try to 'splain with photos.
Anyway, for some reason, the pressure in the middle seems to allow you to easily peel it up with your fingers. I've done this ON the island in the kitchen, as it's the only way I can get some of those lids off, and I've climbed up on our island (we have an old house with very high ceilings) and done that standing up on the island right before racking. Weird, but effective!