How do you create a "Beowulf boast"?
An Anglo-Saxon, or Beowulf, style boast should either reflect something one has actually done and/or something one is capable of either doing or at least attempting to do well. For example, Beowulf boasts to Hrothgar of deeds he had accomplished before coming to aid the Danes. Such boasts serve as a kind of resume, letting everyone know the capabilities of the warrior boasting. He then boasts that he will confront and kill Grendel. He believes that he has the capabilities to do what he boasts, so the boast is in keeping with the rules of boasting in his society. Further, he will maintain his honor, whether in life or death, if he either accomplishes his boast or attempts to do so to the best of his abilities.
To craft an Anglo-Saxon style boast, you would recite your accomplishments and then make a promise to do something. This promise would have to be something that you believe you are capable of doing. After making your boast, you would need to try to fulfill the boast to the best of your ability.