When you set goals for yourself, it is important that they motivate you: this means making sure that they are important to you, and that there is value in achieving them. If you have little interest in the outcome, or they are irrelevant given the larger picture, then the chances of you putting in the work to make them happen are slim. Motivation is key to achieving goals.
Welcome to the club! Great question. There are any number of reasons why we may be unable to achieve a goal by the deadline. Your instincts are on the mark. When you find yourself in a situation where you are unable to achieve your goal by the initial date you set for yourself, revisit the goal. If it is a big goal, break the goal down into smaller goals and set deadlines that are realistic to achieve.
You know what you want to accomplish; now you should begin strategizing what needs to happen to reach that vision. You’ll need to do some brainstorming to identify the main steps and tasks you need to accomplish along the way. Are there certain steps you need to prioritize? Are there any time-sensitive tasks that must be achieved in a certain order? Start determining what needs to happen when.
Achieving complex and difficult goals requires focus, long-term diligence and effort (see Goal pursuit). Success in any field requires forgoing excuses and justifications for poor performance or lack of adequate planning; in short, success requires emotional maturity. The measure of belief that people have in their ability to achieve a personal goal also affects that achievement.