Whether it's on January 1st or some other schedule (I recommend quarterly) it's a good idea to regularly do a deep dive goal planning session.
I hope by this point you know that a goal like "lose weight" is not very good. You've probably heard of SMART. goals which are great, but not the whole picture.
What you need is a goal-setting funnel
A goal-setting funnel is a set of different types of goals starting with the broadest scope, down to the most narrow and specific.
1. Life Areas. This is where you define the top level life areas you're concerned with. For most people this includes things like family, finances, career, health, and relationships. Be as specific or broad as makes sense for you.
2. Emotional Objectives. These are broad objectives that fit within your life areas. They aren't intended to be measurable, but rather things that speak to you emotionally. Examples are "Being a good father" or "Lean and high energy".
3. Measurable Goals. For each emotional objective you'll want at lease one measurable goal. Make sure that your goal is as specific as possible with a deadline and a way to easily determine whether or not it's "done" without ambiguity. Google "SMART goals" if you need help.
4. The One Thing. At this point go through all your measurable goals and pick one that you want to do first. You'll be able to do more in a bit, but to start, pick one goal that if completed would make the other goals easier or irrelevant.
5. Lead Metrics. If your goal is something that you can influence, but not directly control (like how many products you sell) you'll need to decide what your lead metrics are. This means what you do that you have complete control over that you can measure. For instance, you can't control how many pounds you lose, but you can control how many calories you eat.