- why was the document written?
- who gave the information?
- could someone else have given the information?
- how did the informant know the information?
- did they have to verify information in the document?
- was there any motive for lying or modifying the truth?
- was there any real chance of being caught lying?
- was there any punishment for giving incorrect information?
There are other items to consider as well, but these questions may get you started.
And--typing the document is always a good analysis technique as well.