First and foremost, before you jump in and start a subject, take a few days just for analysing. It is good that you have a lot of time left, but it is important to turn it into an advantage.
There is one resource which we do not have control. That is TIME.
Now that you are starting early, you have a little excess of this resource. But it goes away if not used properly.
Turn it into an advantage
Analyse
Plan
Execute
Obviously this question pops up. It is easy to say analyse, plan and execute.
But what to analyse?
How to plan?
What to analyse for ESE?
As you might be aware of, the syllabus of ESE includes technical part and non-technical part as well. Just go and take the most recent paper.
Go through it.
I agree that a lot of people have already analysed the paper and given their insights. But still, it is important to see it yourself before you go on to check what others feel about it. This will give you a feel of what you have ahead in your journey.
What type of questions are asked?
How is the difficulty?
Have you come across such questions previously?
If I prepare, will I be to answer these questions with ease? If not, what to do?
This is just a rough analysis, to get a feel and hold of the exam. With general studies taking about 40% of the prelims paper, it is good to do this exercise. After this, you can also go on to see the key insights from others on the paper.
How to plan, next?
Done with the first exercise? Next comes planning - which is the key. There are a lot of aspects. To get you started, you can start as less as 2 hours per day and plan for the first 2–4 months. Later you can transition to full swing preparation.
The exact planning, and the choosing of resources to study from - you will do on what suits you best, I am not touching upon that.
Focus points
Tech Part: Focus on improving your conceptual knowledge, and approach to questions, especially the ones which you feel are troublesome.
Non-Tech Part: Pick your favourite subject and start light reading. Here we get surface-level questions, so light reading on variety to topics will help.
Generally, we tend to postpone general studies preparation because it is an unexplored avenue for us. Later it becomes for our mind to accumulate a lot of things technical and non-technical.
If you start early on this, it will ease the pressure of your mind, and you can spend a few hours every week in this.
Execute the plan
Okay, you have made an awesome excellent plan. All left is executing it. Consistency is key here. If you have set 1-2 hours per day allotted for ESE, do it consistently every day. Later you can increase the time.
If you can inculcate this habit of consistency, it will bear fruits whatever is the task on hand - whether it is ESE preparation or something else.
All the best! When are you planning to start your preparation?