Difficulty: Moderately Easy
Step1
Stay busy. Often busy people have less time to do other things when they have a set schedule, so cram up everything you need to do leading up to the day of the concert. The person who invited you will realize your hands are too full to be available for that day.
Step2
Make excuses. The one thing that works almost all the time is making excuses as to why you can't go the concert. There are many things you can say. For example, you're feeling a bit under the weather and if you leave the house it will make your sickness much worse or you have to work extra hours at the job and there is no way to work around it. Any excuse that is believable enough can save you from going to the concert.
Step3
Conflicting schedule. Another way to avoid it is mentioning that you already made plans to go out for the evening. Say you really loved to go but you will be hanging out with your friend and you can't back out at the last minute. If the person feel a little bummed, just tell them there always another time to go to one.
Step4
If all else fails, just tell the honest truth that you really do not feel like going because the concert is not your style and you don't like the music that will be playing.