Remember that “no” is a complete sentence and you aren’t obligated to go to any event you don’t want to. Then, try out the CARE rule to politely decline an invite. 

• Consider the invitation by saying something like, “Let me check my calendar” — then remember to follow up with your answer.
• Express your appreciation by saying something like, “Thank you so much for thinking of me.” 
• Respond clearly with your answer, and include a timeline for the person to follow up with you — even if that time is never. (You could say something like, “I’d love to try to make the next one.”)
• Empathize with the person extending the invitation by saying something like, “I hope you have a wonderful time.”