The importance of my goal determines the approach that I will use to make sure to goal is completely seen through. I have two main levels of goals that are split up by how much time they will take, which we can label Short-term goals and Long-term goals. In the following lines I will discuss my approaches to each of the three time limits.
For short-term goals, I use a method that I learned from talking to one of the senior of my high school when I was a freshman. It has been adapted since, but the main idea stayed the same. For all short-term goals (homework, school assignments, etc.), I write them down on a Post-It note and put them on a corkboard I have above my desk. Every time I finish a goal, I crumple up the Post-It note and put it in a container on my desk. Seeing the tasks physically pile up helps me stay productive.
For long-term goals, I tend to keep them in my head and think about them over a couple of weeks. What I generally think about is the best way to make sure the goal happens, whether it be getting accepted to a highly-selective summer camp or making a web application. After I think I have a decent groundwork in my head, I do what I can to see the goal come to fruition.
I am not the most productive person in the world, but I've continuously improved my organization and productivity system to a point that I am very happy with. I will continue to experiment and improve my system, and I hope my post might have given you some ideas for your own systems for task organization and productivity,