A very important part of any campaign is the call to action. If possible always have this call to action, not only does it allow your customer to interact but allows you to measure the success of the campaign.

So when creating a campaign think about why a user would click through. What incentive or benefit have you communicated to them?

The more relevant and personal your campaign can be, the more success your will have. Use {firstname} in the text where possible.

Allow your customer to opt-out. Understand your local regulatory requirements with regard to this. This will allow you to increase the quality of your contact list.

Sometimes it is better to totally untag a person rather than deleting them from the database. This can stop mistakes when reloading your contact list.