Think I’ll put this on my door. 
 

Seems a good idea, might deter alot of the random sellers and unwanted religious people.

Aslong as its not like a "please close the gate" or "do not park here, access needed" it seems to attract more people for most houses. ????

i lock my front gate when i am home so nobody can gain access to my property. nobody wants to try to claim over the wall, as it has thorns and other nasties but looks nice from the outside.

I bought some little stickers that I put on the top of my number 

"No Soliciting". That has cut down on lots of the cold callers.

Still get the odd one though, but we never answer the door to people that we aren't expecting.

We just ignore them; it's very annoying.

It's also horrible to do, as I briefly worked for a windows' company that used to send groups of 5–10 people out into areas trying to sell windows and doors. My parents had new windows themselves and the person handling the sale, ask @GrannyPie if my brother and I had jobs. It's by far the worst thing, but if you have the knack of talking and confidence, then it can pay very well.

I don't waste my time with cold callers, or those people approaching you in the streets trying to sell stuff.

We’ve all had our share of frustrations with unwanted visitors. A simple notice on the door sounds like a great idea. We have to remember that not everyone knocking is ill-intentioned; some are just trying to earn a living. However, personal comfort and safety come first. These notices can help us find that balance.

I've found that a straightforward "No Cold Callers" sticker works wonders. It won't stop everyone, but it certainly reduces the interruptions.

We’ve got a porch so two doors to get through, when someone knocks at the front door I open the inner door and just point at our notice which says “no uninvited callers” so I don’t even have to open the outer door.

I do feel sorry for those folk who are only trying to make a living but if there’s a notice on the door they should respect it and not knock.

I don’t make an effort to rise or respond to the doorbell, even though the sight of a hand emerging from a secondary door and gesturing towards a sign seems quite reminiscent of Monty Python.

A Simple Sticker With the Words NO JUNK MAIL is Fixed to our Letter Box. But it Doesn't Stop the Postman or Woman from pushing all Sorts of C**p through the Door. I Think I May have to make Up some sort of Poster to Deter That. Suggestions Very Welcome.

19 hours ago, Wheelbarrow repair man said:

A Simple Sticker With the Words NO JUNK MAIL is Fixed to our Letter Box. But it Doesn't Stop the Postman or Woman from pushing all Sorts of C**p through the Door. I Think I May have to make Up some sort of Poster to Deter That. Suggestions Very Welcome.

I don’t think you’ll stop the post office putting stuff through your door unless you seal up your letterbox, they are contracted to deliver that stuff so they have to do it.