"If you fail to plan, you are planning to fail." - Benjamin Franklin
I think most people don't hit their goals because they don't plan accordingly. It's not because they are aimless on a macro level, but on a micro level. We often set the long-term goal of losing weight, building muscle, gaining strength, or getting faster. But when we plan for those goals we forget to break them down into chunks that are manageable and specific.
With strength sports, I find that it best to identify the major components of a goal. If that's gaining strength, then it might breakdown into hypertrophy, eccentric strength, isometric strength, and concentric strength. Because each goal builds off the previous one. With speed training, it might be hypertrophy, then strength, then power, then speed. Again, they build off each other.
One of the things I find it important for those who are just working out to stay in shape, however, is the use of undulating your goals. To create training based on a daily outcome that eventually raises all aspects we seek. This is how I program for all of the online programs offered through Littauer Strength Training.
Let's take The Strong Family as an example, a general fitness program based on performance training principles. Each day of the Strong Family training plan is based off of a physiological adaptation, both for strength/performance, and for metabolic energy pathways.
For the strength and performance aspect, each day is focused on either Speed-Strength, Strength-Speed, Absolute-Strength, Power, or Endurance. These goals then help develop the outline the way the day is programmed. The goal determine the sets, the reps, the outputs, and more. For example, we know that power is best developed by performing explosive reps and that our ability to consistently produce power drops off between reps 6-8 (depending on training age). We then can plan our training in set, rep, and weight ranges that allow us to optimize the ability to produce power across a session.
We know that Absolute-Strength is best developed using weights in the 75%+ range (80% for trained individuals) and reps between 1-5. We can then implement training for those specific adaptations to develop muscular strength.
The problem most people have, is that they do not account for the different things that factor into building athleticism and fitness, and they do not plan accordingly. Most adults spend a majority of their time doing high force, long duration movements like heavy squats, deadlifts, bench presses, and of course: curls. Or, they spend their time doing low-weight-high-rep work and spend arduous amounts of time on the treadmill or elliptical. Regardless, they never branch out and develop a fully functional fitness ability.
When we look at planning, especially to reach some sort of health or fitness goal, we need to account for the daily plan. We need to do our best to set daily goals that fit within our weekly goals, and then fit within our major overarching goal. Once we do this, we set ourselves up for better success!