In order to apply for some grants, evidence of having collaborators in another country is often required. How to look for them? Most often, you send e-mails but you will never have answers.
The most effective way is to talk to colleagues during conferences. Contacting authors in your field by e-mail is another way. However, most researchers are already overloaded and do not have time for further collaborations.
The question is important for many who try to climb in the academic leader. It is common for many to ignore you as pointed by Wolfgang R. Dick. They basically believe that there is no incentives to work with you on top the fact that they over worked. My experience is that I that I get a lot of input on my books from outside my field. For example, I get very little input from people in fluid mechanics. They even see me as their competitors or even opponent. Well, I have shown many typical mistakes in the field and basically made revolutions, something that does not buy many friends. However, I get a lot of input and point to typos and mistakes from people from outside the field because they see only motivation of improvement (no competition) . Here the numbers start to play.
If you get other people interested in your work, you will get cooperation of people that you did not expect. I get cooperation or communication from many in the area of compressible flow from people who are electrical engineering and other areas none thermo fluid. I can count only on my fingers the number of people from compressible flow or even fluid mechanics. Additionally, they bring fresh idea on the topic at hand. I can say much on your specific case but let inquiries be known to as many people as possible regardless if think that they are not your demographics.
Finding international collaborators can be a challenge, but there are several ways to increase your chances of success:
Attend conferences and events in your field: Attending conferences and events in your field can provide opportunities to network with potential collaborators and establish relationships.
Utilize professional networks: Utilize professional networks such as LinkedIn or research collaboration platforms to connect with potential collaborators in other countries.
Reach out to academic institutions: Contact academic institutions in other countries that have a focus on your area of research and express your interest in collaborating.
Participate in research projects: Participate in research projects or initiatives that bring together scientists from different countries.
Use online collaboration tools: Utilize online collaboration tools such as Zoom or Skype to facilitate virtual collaboration.
Leverage existing connections: Reach out to colleagues, classmates, or friends who may have connections to potential collaborators in other countries.
When reaching out to potential collaborators, be clear about your goals and objectives, and the benefits that a collaboration would bring to both parties. Be persistent, but also respectful of their time and workload. Keep in mind that building relationships takes time, so it's important to be patient and persistent in your efforts.
I support the advice given by Dr Wolfgang R. Dick and Shezan Ahmed that conferences are a great opportunity to find collaborators. I like that idea more than some of the others because at conferences, people are relaxed and more likely to be happy and pleasant whereas this may be more difficult if people are at work are reading a large number of e-mails every day.
Write one line with your google scholar link and h-index. Tell them you have attached your list of publications. They would download it and read. Don't write a long mail.
In addition to all that has been said, I think it is also important to not just write emails but pitch the project you want them to be involved in. The collaborator you are writing to should be able to see clearly that the collaboration will be added value to them too.