Use this sheet of guidelines to help you deal with 99.9% of telemarketers…
I like it. But it sounds too time consuming. So I think I’ll just stick with the “no thanks” then hang up response I always give now.
Be very polite. But at the first opportunity to speak explain in very clear, an thoroughly insane terms why you are not interested. Do not stop until you are finished. Ignore any thing the telemarketer says. Ignore any questions they ask.
Example-
Telemarketer-Hello, Mister Cathodee. Do you have home owner’s insurance?
DocCathode-I don’t need it. You see the custodians keep the house clean and safe. Mold can never grow in the basement. The windows cannot be broken. The furniture will not burn. You see, the custodians are demons. My grandfather summoned them from the pits of hell to guard this house. When I came of age and became owner of the house, I had to tear out my left eye and give it to the demons. Sure, it hurt. But, in return I get all around coverage, one hell of a security system, and no deductibles. So you see, I have no need for your puny human insurance. Have a nice night.
Then, hang up.
Eh. I’ve definitely seen wittier.
Oh there’s plenty of smarter and wittier retorts to be made. Just ask a telemarketer!! They’ll give you a repertoire you’ll never forget. 
Hey Snoooopy, how ya doin’? Still slaving over a hot phone like this scum-sucking bottom-dweller (me)? 
I have a new plan. I say “No thanks” up front, and then wait for them to hang up. After a long period of time, or maybe as a response to an appropriate question, I’ll ask how long they intend to waste their time talking to me when I already said no?
I’m waiting to try it out.