need help on one business problem

Hi guys,

I am wondering if any of you have tried email marketing? I find email marketing is not working for me after I tried for almost two months. i sell windows and doors, so I write to construction company, developers, but I didn't get much reply.if they are not the right client group? how to find out who will be the most suitable client for me? will appreciate if anyone has similar experience and have a good answer to my problem. thank you very much.