So how do you ensure that your goals are within your reach?
Break them down into bite-size bits. Instead of having one large long-term goal, for example, break that down into smaller, more manageable daily goals. For example, this month I'm working on revisions on the novel I finished in November. Instead of making a goal to finish the novel this month, however, my goal is to do a certain amount of pages every day.
Quantify your goals. My example for the above tip also works for this one. Instead of setting a vague goal, such as to get better at something, figure out smaller steps that can be put into numbers. In my case, I set a number of pages to complete each day. If, on the other hand, you want to get better about marketing, you could set a goal to make one (or three or five, whatever makes sense for you) cold call every morning before you start your other work...or to write one pitch, send out one resume, whatever. You get the idea: Set numbered goals for yourself so that your achievements are clear.
Don't overreach. Even when breaking your goals down into bite-size pieces, make sure they aren't too lofty for you to reach. For instance, don't make your goal to catch up on the entire week's work all in one day. Set little goals to start out; if those prove too easy for you to accomplish, you can simply set another goal for the day, or try setting a slightly tougher goal the next day.
As for my goals for the month -- I'm falling behind, and considering how busy I am this month with other stuff, I think I set my sights too high. Never feel ashamed if you have to scale your goals back -- it's better to accomplish what you set out to do (even if it's a little less) and stay motivated than it is to continually fail and eventually get so discouraged that you give up!