How to Increase response rate

[Alejandro Flores]

So I been marketing with yellow letters first couple of months the response rate was at 2-6% response rate, now it has gone low as to .5%. It's been 5 months since I started the campaign. I been using similar letters, and there all handwritten. I also notice that there are more less motivated sellers then the first couple of of hits. But first, How can I improve the response rate? What are some different ways to approach?