A dating profile should include the most basic information about yourself, including likes, dislikes, hobbies, employment, talents, preferences and at least one picture. Keep in mind that a dating website is not an employment website; it's best to avoid being too formal.
Most dating websites tend to provide you with a basic template of what information to provide about yourself. They also ask or require that you submit a photo of yourself, as profiles with photos are approximately 50 percent more likely to be contacted. Photos are usually head shots, stopping around the shoulder area; "selfies" tend to be fine, but may create the impression that you aren't as interested in your profile as others might be.
In terms of the information you wish to provide, it helps to mention only the good and attractive attributes; if a relationship does indeed begin to grow, your partner will have ample time to get to understand you and your negative attributes. Don't exaggerate, as it is usually obvious and discourages potential partners. Having an interesting job is always an attractive quality to mention. If you have pets, this is also good to add; taking care of a pet tends to be a good sign that you are comfortable with attending to others' needs and time.