John Gardner once sagely observed that writing exercises were good practice because they were like the writing life, much of which consists of inventing stuff not because you particularly want to but because it is vitally important for what you really want to write.
Start the story with the main character as a child. After a period, the story really starts moving again with an adult.
BUT it's important for the reader to know some of the things that happened. So that you know that the princess is a pain, or how the main character is unpopular but beloved of a few who know him well.
It is possible to have a -- comic -- story about a character who blunders from success to success. Who solves people's problems by accidentally saying the right thing for entirely selfish reasons. Who accidentally stumbles on solutions to puzzles and finds lost items underfoot.
That has to be the only mode of operation. Perhaps the character can do something right by intention up front, but then be trapped in a cascade of situations where the comic blundering saves the day. But having a character flipflop between dumb luck and shrewd -- or even commonsensical -- action breaks the unity of the theme and plot
