The solution for that is “DO NOT SEND GENERIC PROPOSAL AGAINST EVERY JOB”
THE BEST PROPOSAL WOULD INCLUDE FOLLOWING THINGS:
1- Write Greetings, like hi, how are you etc.
2- Tell the buyer you understood his requirements, don’t just say it, repeat the job in your own words i.e. I see you want the job done by having a popup which will appear when anyone lands on the website”, then tell about how will you accomplish it.
3- If you have any question or suggestion, write on 3rd place.
4- Let the customer know about your experience i.e. I have this much experience, and I did this much websites/or projects so far.
5- Tell the customer about your availability, i.e. I am available to start the job right away or as per your ease.
6- Share the best of your work, i.e. around 3 to 4 links, try them to be relevant to user requirements.
7- Call to action like “If you’ve any question then feel free to ask”
8- Good bye greetings, and that you are waiting for his response to discuss further.
Nobody is perfect, if you have better suggestions, please share.