Setting goals doesn't appear to be difficult. You just establish a specific goal, one that's measurable and has a defined time frame for completion.
On the surface, it sounds easy enough to do.
You implement the plan, measure progress towards reaching the goal and then evaluate the outcome objectively to refine the process.
But it rarely seems to work out that way - for a variety of reasons. The primary one is because we often fail to establish realistic goals.
Additionally, we often casually set goals with only a hazy view towards how they'll actually be accomplished. And while we're typically motivated at the beginning of the process, it's not at all unusual to lose this drive somewhere along the way.
When preparing your own goals, it's important to first understand that every goal must be realistic and readily achievable, given an appropriate amount of time and resources.
Read more on Goal Setting here