By sure fire way, do you mean like holding him or rocking him? Yeah, I mean if I hold him upright in my arms he'll sleep, but he'll wake up as soon as I put him in his crib or swing. The other method is breastfeeding but I think that doesn't help the pain or discomfort... Since it might cause more gas, reflux etc.
As for distinguishing between OT and hunger, you are absolutely right. I have no idea how to tell between the two because I think in both cases he tends to try to look for something to suck. The. When I fail at putting him to sleep and finally give him the breast, he just suckles for 10 minutes and falls into a deep sleep (I and even burp him when he is so deep in his sleep!).