Briefly describe your feature. If others are doing similar work, it's OK to acknowledge them and summarize how you're different. Suggest sections or locations in the newspaper or publication where your feature might be anchored. Summarize in two sentences what a syndicate sales person might tell a publication editor about your feature. List your address, fax number, e-mail, day and evening phone numbers.
Some creators send out simultaneous, multiple submissions to other syndicates.
Editors appreciate a brief note if it is a multiple submission, but it's not required. Creators who have talent and experience in a variety of print forms are attractive to syndicates. A syndicated column and a book can enhance each other. Some syndicates seek newsletters that can add another dimension to material that can't appear in the column. The lecture circuit is a good place to gather column material and mention your column.