You can choose to have your campaigns run through a spam checker during the Preflight Report on the Preview and Send step that checks for characteristics of spam based on common spam filtering software. This feature will return a report and highlight any aspects of the email it considers to be at risk. The various messages displayed all allow you to pinpoint the areas that need to be corrected, and steps can be taken to minimize the chances of your campaign being classified as spam.
Most spam blockers are based on words in the sender's name, subject or email content that refer to money, special offers or opportunities. The usage of text such as Limited Offer, Opportunity To Invest or As Little As $2,000 will get the attention of most email filters, as will the unnecessary use of capitals or symbols (e.g. !!!, Save $$$).
The rules for Junk mail folders will vary depending on which email program the recipient is using. For example, the settings for Outlook's Junk mail filter are set by Microsoft and are based on the content of the email (i.e. certain words).
Recipients can generally prevent campaigns from routing to their Junk mail folder by adding the sending domain (e.g.emailcc.com or your custom sending domain) to their safe senders list.