Who are your customres?
Contractors? Home owners?
Yes the letter of introduction is a very good practice asspecialy if you provide the local service, or supplie locally.
I think it helps a lot to introduce yourself.
You can just write with the nice de_script_ion of what are you offering.
don't expect a lot of calls from that letters but be patient and maybe send the second letter in about a month or two reminding people that you areavailable.
Remember people will have to hear about you couple of times sometimes 5 tiems before they consider you for a project.
I am in the
hardwood floors busines and have send 400 letters and never heard from anybody, I have repeeted this three times.
Now when I look back at my clients I have got about 6 very good contractors that are giving me jobs sometimes.
So it is hard work and will pay off later.
Good luck..