i try to lead by example and when people ask me why i choose this lifestyle, i try to explain it in a way that doesn't seem like i'm "pushing it down their throat". just remember what is was like before you were vegan, and try to relate to people's skepticism and answer any concerns they have. i feel like veganism speaks for itself, and if you lay down the facts people can come to their own conclusions.
if they stop after a few weeks, remind them that while they may be having trouble adjusting, it's far a less a sacrifice than all the animals who are raised in their own feces and brutally slaughtered to feed someone who could easily live without them. AND that it takes about a month for you tastebuds to adjust. AND that they are not the only creatures on this earth that matter, and they should stop being so fucking selfish!!! ok, maybe that won't help MOST people, but it feels great to say it...