A short builder
Say what you're being asked for, and who is asking. You get a no you can say out loud, in one line, with a second line only if you want one. Nothing is saved.
From the note How to stop people pleasing: the yes you give while meaning no. New here? Read it first, or just start below.
First
What are you being asked for?
Pick the closest one.
Second
Who is asking?
This only changes the wording a little.
Third
Do you want to offer something else?
You don't have to. A no with nothing attached is complete.
Anything in a coloured box is yours to fill in. Say it out loud once before you use it. Change the words until they sound like you.
What to leave out
After you have said it, it may still sound rude to you: "I had no time for them." There is a second sentence that is just as true: the truth of it is that I kept time for me. Write down the date, so you have the evidence.
The note has a way to catch the yes before it leaves your mouth, and the one-week yes log shows you what each yes is paying you: The yes log.
If saying no has been hard for years, that is a conversation more than a tool. I keep a free 45-minute call open for exactly that.
Occasional, when something is worth sending. No schedule to keep up with.