Some newspapers prefer to do the write-up themselves, which allows editors to tailor announcements to space and formatting requirements. If you're submitting an announcement to one of these papers, they might ask you to fill out a form with just the information they need. Other papers will ask that you write the announcement yourself, and they'll edit it accordingly for publication.
The most common details to include in your announcement are your name and the groom's, the names of your parents, the ceremony and reception venues, the wedding date and the minister's name. Additional information may include the honeymoon destination, the location of your new home, a description of your dress and your mother's dress, who gave you away and a photograph of you and your fiancé.
The key to including all this information in your announcement is to keep things short and sweet, without using fluffy wording. A bare bones announcement could also cut down on cost since some newspapers will charge you more for lengthier submissions. If you've got the money and space to get wordy, feel free to do so -- some couples even add a short blurb about how they met to make it more personal!
To get an idea of how to write your announcement, just pick up a newspaper and read some examples for yourself. Don't forget to ask someone to double-check your information. You definitely don't want misleading information or spelling errors to go unnoticed.