Talk to your customers, ask for advice. They may come up with referrals. They may get you in touch with similar companies. That's how we do for https://www.testinvite.com
When we have a new customer, we try our best to expand over.
We ask for back links if it is a small business.
If it is a medium size company, we ask who they can introduce us in similar companies. Even though these are their competitors, they don't bother introducing us or giving the right contacts.
IF it is an international company, we ask if they can introduce us in offices in other countries.
PS. That works for us because our product is a software as a service.
Talk to your customers, ask for advice. They may come up with referrals. They may get you in touch with similar companies. That's how we do for https://www.testinvite.com
When we have a new customer, we try our best to expand over.
We ask for back links if it is a small business.
If it is a medium size company, we ask who they can introduce us in similar companies. Even though these are their competitors, they don't bother introducing us or giving the right contacts.
IF it is an international company, we ask if they can introduce us in offices in other countries.
PS. That works for us because our product is a software as a service.
Hope that helps