It is advisable to provide a detailed outline of the artist or group’s history, emphasizing particular achievements (i.e. awards or honors, performances at particularly notable venues, etc.) and providing quotes from articles contained within the support materials. If support materials contain testimonials, these should be specific, listing particular accomplishments and descriptive information, people writing a letter on behalf of the beneficiary should provide information that speaks to their own credentials. For any articles, USCIS advises that petitions provide detailed information about the publication such as circulation, a clear identification of the name, intended audience, and reputation of the publication, and for any online-only sources, any available information about web traffic numbers would be helpful. Remember that any material not in English must be accompanied by a full translation with certification.
In general, be extremely thorough and provide evidence that speaks to the reputation of not only the artist, but of venues, previous employers, any awards or honors, etc. Do not assume USCIS adjudicators have any familiarity with the arts and publications, artists, or venues that may seem well-known. Most RFEs question prestige and reputation (of everything) – anticipate this before filing, in case you do not get the chance to respond to an RFE.
Finally, even when engaging an artist who has previously received visa approval, prepare future petitions as thoroughly as if this is a first-time filing. USCIS has made it clear that prior approval is no guarantee of future approval.