Invitations to private views and talks are a good way to attract new audiences. Current audiences have the opportunity to show these to other people, to bring them along and introducing their friends to you and your work.
The imagery you use on one side of an invite is the primary way in which new audiences will make snap decisions about whether they will come and see your work. Text on the reverse provides you with a second opportunity to set expectations about the event; date, location and time being obvious, but also other background information. Details of any sponsors and any comments about the work can also be included. Think of the way in which a book jacket is used to promote the contents. Reference your website if you have one.
Although printed invitations have fallen out of favour recently – and the cost of printing and posting them has become prohibitive for many artists – a well-timed invitation posted to an influential contact may induce them to attend, or to show the image to colleagues who may be interested in your work. See if you can print a small number of invitations cost-effectively, or reuse postcards of your work for multiple exhibitions and replace the information with stickers on the back.