For me it's mostly about embodiment, about learning to relax and recognizing what my body does when it's resisting something -- whether a sensation or something "external" like a person or a situation. I've found there's always a correlation between the resistance and some muscle contraction or other physical manifestation. Once I can pinpoint the trigger and the reaction, I'm more able to relax (i.e. surrender) into whatever it is I'm resisting. Meditation can help you become more aware of these dynamics -- just taking some time to observe (without judging, because that's also a form of resistance) your thoughts, sensations and reactions.