the typical new years resolutions is something like "i will lose x pounds" or "i will finally finish reading that book.'" the problem with those resolutions is they are goal-oriented. personally, i think that is a mistake. the resolution should not be about the goal, it should be about the process to reach that goal.
the ideal resolution is two things: (a) it should improve the resolver's life somehow, and (b) it should be achievable. too many people focus on (a) rather than (b). by focusing on how the resolution will be achieved, i find, i am much better at keeping them. goals are aspirational. but they don't tell you what to do on a day-by-day, moment-by-moment basis. but that is how we live our lives. to be achievable, you need to focus on what you're supposed to do, not where you want to end up.
so instead of coming up with a goal-oriented resolution, i suggest coming up with a process-oriented resolution. rather than defining the resolution as the goal of what you want to accomplish, come up with a plausible plan and then make that plan the resolution. so instead of "i will lose x pounds", make it, "i will stop eating x" or "i will spend x time on the treadmill".
that doesn't mean you have to make yourself an easy resolution. it's more about just being realistic. my resolutions are always about process. for 2011, for example, i told people i was resolving to become a chocolate snob. but really i was resolving to not eat non-fancy chocolate for the duration of the year. that's what i mean by process oriented. if i had left it at "i will eat better chocolate", i don't think it would have worked as well because it is endlessly debatable whether my overall chocolate consumption is better or worse than in 2010. knowing that i am not allowed to eat M&Ms, hershey bars, or any chocolate that doesn't have a percentage of cacao printed on the wrapper is easy to apply on moment-by-moment basis.
i've also developed a short list of principles i try to keep in mind when i craft an achievable resolution:
(1) keep it as simple as possible. it's easier to follow 1-3 lines of instructions than a whole paragraph.
(2) resolving to not do something is easier than resolving to do something. for whatever reason i am a lot less motivated to do something i don't otherwise want to do than to swear off something i like.
(3) the terms of the resolution have to be clearly defined. judgment calls just gives me wiggle room for cheating. the problem is that spelling out concrete boundaries and plugging loopholes make the resolution more complicated, which conflicts with principle #1.
(4) the resolution should expire. resolutions are experiments. when i make them up, i can't be sure whether i will like the result, so it is better if the resolution only lasts for a limited duration. also having a light at the end of the tunnel is a better motivator to follow the rules than if i'm telling myself this is what i have to do for the rest of my life. give yourself a date when the resolution ends. that's a chance to look back at how it went and decide whether you want to keep doing it after that. typically, my resolutions are one year long, with an option to renew after that.
actually, my resolutions rarely follow all four principles. but they are something i try to keep in mind when i do my resolving.