Describe a time when you tried to do something but weren't very successful. You should say: when it was what you tried to do why you were not successful in doing it.

I want to tell you about a time when I failed but eventually achieved success. It was during the Young Reader competition. For two years in a row, I participated in this contest, but I couldn't pass the regional stage. It was a very disappointing time for me because I had worked so hard. I [...]