usually, I contact the high DA website to seek cooperation but they don't reply my Email even after my several Emails reaching out to them. So sad and depressed at that moment. Any good ideas to improve the cooperation chance? Thanks in advance.
You need to be able to tell them the answer to the basic collaboration question: WIIFM? (What's In It For Me?) What would a successful website gain by cooperating with you? Perhaps if you can post your thoughts on these reasons, we can provide a bit more help for you.