There's an acronym for exactly that, and it's SMART: specific, measurable, actionable, realistic, and timed. I'm sure many of you are already familiar with this, but a refresher is always good, right?
1) Specific - Are your goals too general? "I'm going to lose weight." Probably one of the most commonly set goals around the world, and simultaneously one of the worst. If you wake up tomorrow and weigh .5 lbs (or kgs) less, did you accomplish your goal? It's very important to set specific goals. Take time to analyze exactly what you're hoping to accomplish and build a little detail into your statement.
2) Measurable - You should be able to determine if and when you have achieved your goal. If you set sufficiently specific goals, you should have no trouble with this. Your resolutions or goals should have concrete measurements which define not only when you have achieved them, but also how you are progressing towards success.
3) Actionable - Your goals should have steps that you can take immediately to begin the process of reaching them. Simply setting a goal of making $1,000,000 by the end of the year isn't very useful unless you have some concrete actions that you can take to bring about the result. Set resolutions that lend themselves to taking action.
4) Realistic - A resolution should be accomplishable. It's great to pick something that will stretch you, make you grow, or test your resolve, but make sure that it's possible for you to achieve it. Don't aim for something so unrealistic that you are doomed for failure - it will make it harder to stay motivated, and could hurt your drive and ambition in the future.
5) Timed - Your goals need to have a defined point at which they are resolved. In the example of weight loss, you not only need to define how much you plan to lose, but also WHEN you will lose it by. On top of that, you should probably include parameters for keeping it off. Do you really want to lose those 15 pounds by May, but be back to your original weight by December? Of course not. Be specific about the timing of your goals as well as what you are trying to accomplish.
Many people have already set their New Year's resolutions, but these are great guiding principles for any type of goal setting no matter what the occasion. Applying the SMART principles will make you much more effective in setting yourself up for success.