Don't be afraid to refuse others.
Smile when you refuse. Don't make up excuses For example, your sister's brother-in-law wants to go to your house for the weekend, but they are lazy and you don't want to keep them. You can't say "I'm going to clean for a long time", you should say "this weekend is not good, we have other plans." If they still insist, you can say, "I'm going shopping and cleaning this weekend, so I won't keep you." I hope they don't insist on staying. This is not a fabricated reason.
Even if the other person is impolite, be polite when rejecting the other person. Whether you are a salesman or a friend, you can politely refuse.
Before refusing, say "I can understand your situation". If the other person is reasonable, he won't mind being rejected.
If your refusal makes the other person unhappy, you should also keep calm and leave if possible. If you can't leave, change the subject, or praise each other gently.
It is best to be one-on-one, but if you are not used to rejecting others, you can bring a mature intimate friend and simply explain the reasons for refusing. For example, say, "I'd like to help, but I've been too busy recently." How about next time? "You don't need to explain further. Otherwise, the other party may be unhappy and think you are making excuses. It takes courage to refuse other people's demands, but sometimes it is necessary. When you can't or don't want to do something, you should have the courage to refuse others in good faith and firmly. You need some practice to prepare.