To me, verbal diffusion is the key. While doing this I maintain a short distance (just out of punch range, but within snap-kick range, if I know the person to be violent I usually try to keep a bit back), hold my hands open, palms towards them at between my waist and chest height (once again depending on A. If I know the person to be violent. B. If I don't know the person at all.) And talk calmly, clearly and softly, but not as low as to let them think I'm muttering things under my breath or anything (hey, some people are crazy! ) While I'm doing this I "scope-out" the target, (body-language, size/ fitness= as to estimate speed and strength etc., take note of any stances shifting of weight=may tell me of an incoming attack and if they've had training and eyes=tells me if they're intoxicated or whatever, may also give away a possible attack). I also take notice of surroundings (any friends he has, possible weapons, proximity to walls/obstacles etc.) If a person makes a grab for me, depending on my risk assesment strategy I either leave it (If I know them to be all talk) or use their force to spin them around/ put off balance (works well if they're not overly fired up but drunk from experience. Granted, this one is more for people you know/ don't particularly want to hurt). Put them in a pain compliance hold (More sober people). I've found when facing someone who has induced a stimulant, eg. speed, it is better to simply dodgeand weave until you have a chance to escape (unless I felt if they would vent on someone else, in which case I would try to position myself for a pacifying strike, eg. K.O., nerve-strike(?)maybe a break of some kind).. All after the grab applies unless they have a weapon, in which case I would A. Apply a pain-submission technique that would disarm them, or a Aikido throw that left me in control of it/out of reach. B. If I believe that I'm in imminent danger I would either go for a break move (hapkido aikido throw or a hard knife-hand to the throat/bridge of nose (exact target would rely on whether or not I believe that the opponent would get up/ continue the altercation with a broken nose. I'm just speaking from experience and what has and that (from past experience) I believe would work. Please feel free to critique and ask questions and I will do my best to give you a satisfactory answer!