Its that time of year when people start reassessing their lives and thinking about what's coming up next.  Last year I got really serious and wrote myself a goal list.  Some of my goals were good and were achievable, most of the others were not.  So this year I've

1. Goals must be achievable - One of my goals for last year was to pay off my credit card.  Unfortunately, there was no way I was going to have enough money available during the year to reach that goal.  I would have been better off saying "I will pay $500 off my credit card". 
2. Goals should be able to be achieved once and for all - One of my goals last year was to exercise for 20 minutes once a week, every week.  While that was very noble, it meant if I got sick for a week and couldn't exercise, I'd completely blown the whole year.  A better goal would be "I will exercise 52 times this year", that way when I hit the magic number I would be able to say I had achieved my goal.
3. Goals should include things that can be done immediately - Most of my goals last year were things that couldn't be started, much less achieved, until later in the year.  It became very disheartening as I wanted to feel that I was getting somewhere and achieving something, but I had chosen goals that were so far off I couldn't do that.   This year I have made a point of choosing at least some goals that I can start work on today and finish relatively quickly.  These include some such as "Finish my cross-stitch", "Pack up the girls baby clothes".
4. Don't be afraid to reassess your goals - Life changes and circumstances change.  If halfway through the year I have achieved my goals, I will look at setting some new ones for the second half of the year.  If I have barely done any in 6 months, I'm going to reassess them to see if they're realistic based on the current circumstances and maybe set new ones instead that I can achieve in the remaining time.  Or else look at what I need to do to allow myself to achieve them, e.g. if I'm trying to pay off my credit card, maybe I need to set up an automatic B-Pay which will let me do that in time.
5. Write them down and put them wear you can see them - Both last year and this year I have typed up my goals and have put them in a number of places to remind myself what I intended to do and to encourage myself to get started.  I have one on my bedroom wall where I can see it from my bed.  One on my bathroom mirror, one on the pantry door in my kitchen, one at work, one in my diary, one in my purse.
6. Tick them off as you achieve them - There's such a sense of achievement when you see the number of ticks on the list on your list growing.  If you're trying to achieve something with a number attached to it (such as exercising for 52 times in the year), keep a tally of it because as you see the tally growing it will encourage you even more to keep going.

I personally find goal setting to be really invaluable.  It helps to focus me for the year ahead and to help me feel like life is more than a routine of "get up, feed kids, go to child care, go to work, pick up kids, dinner, bath, dishes, bed".  I find without these guidelines that I only set "resolutions" which seem more to be hopes, rather than achievements that have a finite finishing period.  Something such as "I will quit smoking" is hard to achieve because you never know when you've given up long enough to truly say you've achieved it.  If you say "I will not smoke for 30 days" then at the end of 30 days, you know you've achieved it and you can do that over and over until it isn't a meaningful goal for you anymore.