When a homeowner receives your direct mail for the first time, chances are they will ignore it but when you keep on sending direct mails to the same list of people then you're creating brand awareness and building trusts which are the key factors of any business.Also, handwritten letters will not increase the response rate rather you can use a handwritten font. 

I didn’t know which font to use to portray sarcasm lol.

HahaBut I’ve seen professionally printed signs in single color and use a font that looks like hand writing.I understand printing in color costs more, but why not make them at least look nice or use a logo.

Experimented with different colors, font, messaging, and even language.

Most of them have handwritten fonts so you won't have to hire anyone to handwrite your mail pieces.

The thing that's great about @James Carlson is that he's a veritable font of useful and important information, not just some hack shilling his wares or cramming his uninvited opinions into other people's threads (:ahem: me).

Check out NC GS 42 on all of the specific requirements for completion of the Option agreement, including font size requirement, as an illustration.

Try handwritten fonts for both envelopes and letters.

I've done that multiple times for various subscriptions that had some asinine cancellation term buried in their 6pt font 20 page terms and conditions, and for companies that made cancelling impossible because of a lack of responsiveness.

If they font reach out I don’t head over there.