Perhaps a useful way to understand the nature of resolutions might be to divide them into categories:
Resolutions of being
Attempts to change character (or attitude, if you prefer to think of it more flexibly)
Popular examples: I will stop being lazy. I will be more compassionate.
Resolutions of action (or restraint from action)
Attempts to change behavior.
Popular examples: I will exercise every day. I will stop smoking.
Resolutions of result
Promise to reach a specific goal by the end of the year.
Popular examples: I will lose 100 pounds. I will make $1,000,000 dollars.
-- Fuggidaboudit. Life has to co-operate, and life is a non-co-operative beast.
Clearly, resolutions of action hold the higher possibility for success, as they by definition include the element of deliberate control. But wait -- many of these are attempts to change habits, and many, if not most, habits stem from character to some extent (e.g., the inherent trait of laziness is sometimes a reason for not exercising every day).
So maybe the trick is to define the task as a specific action you can force yourself to do, despite your lazy, selfish, cowardly, bad-attitude self, and which is physically under your control despite whatever time-and-energy-sucking gotchas life throws at you.
Good luck finding a worthwhile resolution that fits that definition.