Your first goal in Jiu Jitsu should be to survive and be comfortable in the worst positions.
Our instinct here is to fight, struggle, and push but these things only make it worse. There will be an opportunity to escape if you are patient, but if you aren't it will be your demise.
Unfortunately, there isn't a quick fix that will give you this skill. You just have to train, get there over and over, and practice remaining calm.
I use to get claustrophobic underneath my opponents and tap out due to fear. I would cry after training when I was 12 and 13 and get frustrated (the picture featured was taken around 13 - I'm on the bottom getting choked). I was lucky though to be in a family where training was just what we did. And I loved it! That was why I was so frustrated.
Over time, I became comfortable on the bottom and recovering my guard, but I couldn't do anything with it. Well, eventually I was recovering guard enough that I began sweeping my opponents occasionally and getting to the top, but I couldn't hold it. Well, eventually I began getting to the top enough that I started to learn how to stay there and control my partner, but I couldn't submit them. But then eventually I was staying on top enough and controlling my opponents that I started catching some submissions when they would inevitably make an error because they panicked on the bottom.
The circle was complete.
But this journey is not unique to my experience. Many of the best practitioners in the world were not dominant in the beginning. In fact, hardly anyone is unless they just happen to be the biggest or most athletic person in the room.
Learn Jiu Jitsu this way, and you will be comfortable and capable in any position or situation. This experience will give you confidence in all aspects of life and remove the majority of the fear of fighting (there should always remain some).
Remember that it will be a long journey. There are literally hundreds of techniques that you will learn along the way to acquire this skill. It will take hard work, dedication, and lots of patience. There are no short cuts. There aren't any tricks. And that's exactly why it's so rewarding. In a culture that increasingly is forgetting the value of working hard and putting in long hard hours to cultivate a passion, complete a task, or achieve a goal, having the patience to just keep showing up and believing in the training will be extremely fulfilling.
Best of all, this has given me the patience and compassion to teach someone else Jiu Jitsu. I LOVE to pass on this skill to others because of what it has done for me. If you haven't started your journey yet, what are you waiting for? Don't think about it any longer, just pick up the phone and set up your first session.