The most common brand naming mistakes include treating naming as an afterthought, underestimating the importance of a good creative brief, trying to sound like other players in the industry, forcing the name to include what the company sells, and not seeking feedback. Other mistakes include choosing names with questionable meanings, weak branding names, and unpleasing foreign translations. It's also important to avoid mistaking the name for the brand, looking for a "likable" name instead of a strategically sound one, lacking criteria for defining a good name, and prioritizing memorability over other important factors.