Re: Struggling hard..
You're not alone. I am in the same situation. But it shouldn't disappoint you and you should never look down at yourself and your research. If you like your field of research, then that's the important thing, you will definitely reach a point that you have many publications.
Re: How do people produce so many work in such a short time?
In my experience, there are different reasons:
- They are continuing a research and they take different approaches to
solve it.
- The papers are not sent to quality journals.
- They are based in a strong team that helps them.
- They are familiar with the tips and tricks of publishing in a
specific journal.
Re: Publishing in short time
Unfortunately sometimes people are not very honest, so simply don't listen to them. Like so many things in life, stick to your idea and don't criticize yourself by comparing yourself with what other people claim.
Also, when you want to publish, you can check the editorial process time; it can save you a lot of time (you can check my response here: How to find Elsevier journal-specific average publishing time).
Also make sure that you're sending your paper to the right journal. You can do this by reading the abstracts and conclusions in some of the articles in that journal.
Re: What am I doing wrong?
You are doing nothing wrong; like me, you are in a learning process. Publishing papers requires its own skills and we are both learning it. Nowadays there are some online courses that can teach you the skills. I haven't checked them myself, but we can get some ideas from them (e.g. https://www.udemy.com/publishing-in-impact-factor-journals-tips-and-tricks/)
Re: My adviser says my progress is good
My two journal papers during my PhD was rejected and I was so disappointed. But same as you, my supervisor liked my research and contribution. Since it wasn't mandatory for me to publish journal papers to get my PhD and I just had to submit my thesis for external examiners to review and comment, my supervisor asked me to focus only on my thesis. Now the thesis is finished, I have time to learn how to publish.
Besides, I personally don't agree with 'Publish or Perish' idea. I didn't publish anything, but I managed to demonstrate that I like doing research and I have other skills. With that, I didn't get an academic job (with no publications), but I manged to stay at university for a part-time research assistant job, so I can have some time to learn and publish.
Last humble advice:
I'm reaching out to people and I talk about my research field and I'm asking if I can contribute in their articles; it will give me a chance to learn how to publish and also have my name as co-author.
I hope it helps and I wish you all the best.
Just don't give up :)