The first step in any fitness routine is to determine your goal. That goal should be specific and measurable. For example, you need a goal like "lose 30 pounds by the end of the year", "run in the next NYC marathon", or "step on stage at the spring bodybuilding competition". These provide a timeline and a way to measure success. Examples of bad goals would be "get in shape" or "get a tighter stomach".
How do I pick a goal, you may ask.
First, your goal has to have a definitive end date. This date needs to be reasonable but also less than 1 year away. This will give you something to count down to and also put pressure on you to push yourself when it is difficult. When in doubt set smaller goals. Achieving a goal will bring you confidence and a feeling of accomplishment. Then you can set a new goal for yourself.
Second, your goal should be measurable. In some cases this is very simple. If you are training for a marathon, you record mileage and times. If you are training for a bodybuilding competition, you should record your weight, body fat percentage and take progress pictures. You can't manage what you don't measure.
Third, let others know about your goal. Some people have difficulty doing this, but being open and honest brings accountability and encouragement from your friends and family. Regularly post updates and share your accomplishments or struggles. Let people cheer with you at your victory and also support you when you fall short. As a bonus, you get the opportunity to unfriend/unfollow those people in your life who are less than supportive.
Lastly, pick a new goal when you achieve your first goal. You should always have a goal to work toward. I have seen so many people achieve a goal and then they become aimless. For example, if you set a weight loss goal of say losing 30 pounds. Once you have achieved that goal, you have to celebrate and then quickly set a new goal to work towards. If you don't, you will become complacent and your workouts and training will suffer and often you will end up going backward. For example if you are training for a marathon or your first 5K, once you have done the event you need to pick another event to work toward or you will have no motivation to get in the gym or out on the road to train.
Good luck and get out there and climb the mountain!