You will need letters from friends, family members and associates. These letter must include the letter writers original signature, date, address, phone number and citizenship status of the writer. A good letter written by one of these people will explain how they know the alien and qualifying relative, and for how long they have known them. It will also be relevant to discuss the relationship between the qualifying relative and the alien. A good letter will explain any changes the writer sees between the qualifying relative now and the qualifying relative he knew prior to the existence of their relationship to the alien. Specifically we need information about how the alien has made a beneficial impact on the life of the qualifying relative, with examples of the changes wrought, if possible. The letter writer may also give their opinion about the impact that the separation of the alien and the qualifying relative will have on the qualifying relative.
Document whatever extreme hardship is present
You need to gather all medical, psychological records, letters from physicians and other records that could tend to show that the burden for extreme hardship for this qualifying relative should be less than for others. Prior medical/psychological problems are good in a waiver case, in that they can show that the qulaifying relative needs the alien around to avoid these troubles.
IMPORTANT! Letter from the Qualifying Relative
A letter from the qualifying relative. This letter should talk about the alien and the relationship, and should attempt to draw a word-picture of the qualifying relative before they met the alien (feeling "less than") and the qualifying relative since they met and married the alien (feeling "more than"). Any quality improvement in the qualifying relative's life that can be attributed to the alien's assistance should be so attributed
OFTEN OVERLOOKED! Letter from the Alien.
The alien in an inadmissibility case needs to explain why they did what they did to make themselves inadmissible. The alien needs to help the officer understand, and make it reasonable that they would do what they did, whether that was lying, entering the US illegally, or what have you.