Using i we in an essay, when is first-person writing ineffective or unwarranted?
Another, easier and more accurate, way is to use a computer to search through a large collection of essays. You can search corpora that already exist, using a 'concordancer' or other types of software, or you could even build your own corpus if you want to investigate a particular type of text and you can't find an existing corpus.
Sometimes, the best hook is a personal anecdote, or a short amusing story about yourself.
An obvious way of finding out the answer to this question is by searching through successful essays. It gives the reader the wrong idea about what "we" who are we?