How to say no without sounding like you are difficult or arrogant

Some people will test your boundaries. They will guilt you and try to get you to give them what they want. Don't do it! Once you say yes, they will constantly ask you. And you don't have to come across as rude or indifferent. Just say it with a smile. And be firm, yet polite. People have to know you won't give in to guilt. Otherwise, you will just be a door mat that people can walk all over.