First and foremost, email campaigns should always use a subject line thatís straight forward, not misleading. The subject line should be 100% relevant to your emailís content. Avoid using spam words in your subject line like: FREE, fast cash, Act now! Avoid using all caps, exclamation marks, and dollar signs, as these symbols and words often trigger spam filters. For a complete list of spam words to avoid in your subject line, click HERE.