There are many ways you can goal set. You've probably heard of SMART goal setting. Personally I like to use a type of goal setting could GROW as it focuses more on raising awareness of your current reality.
Let's put pen to paper and get into it. :) Goal - (set your goal) For example if you want to loose weight, how much do you want to loose? What is your BF% goal? What dress do you want to fit into? Why do you want this goal? (create some emotion around your goal, dig deep for the real reason, this is what is going to get you moving on the days you feel less motivated. Reality - What is your current reality? Where are you right now? Get real with yourself on this one, in order to move forward you've got to face the truth in order to move forward. How much do you weigh now? What dress size are you? Are you happy? What emotion do you feel right now? Are you happy in your current environment? Options - What options do you have available to you? Do you need help? Could you reach out to a coach, nutritionist, physio? What books could you get to help you? Where can you get advice to help you achieve what you want? Do you need a training partner? Can you change your environment? Will - What will you do? Write down your plan and your daily steps that are going to help you reach your goal. Write down the days you're going to check in with yourself to see if you're on track. Who is going to help you and when are you going to get started? What good habits are going to replace the bad ones?
If you find yourself falling of the path to your goal then return to your goal setting steps. Maybe something isn't quite working and you need to plan again and implement something different. Remember most things worth having require the most effort :)