Make sure to not crowd the card by only listing top priority points on the wedding invitation. These points include the time, place, hosts, names of the bride and groom, and RSVP details. If you want, you can also include the dress code for the ceremony, but you do not have to. When you try to put too much information on the invitation, it can get hard to read and look chaotic. Make sure to never list gift registry information on your wedding invitations. This bit of info should only ever be listed on your wedding website. It is not respectable to put these sort of details on your invites under any circumstance.
Keep in mind that invitations do have an important job. No matter how carefree or nontraditional you and your fiancé are, the invitation should include the date, time and location of the wedding and the reception. If you expect a response from your guests, it is also important to include a self addressed envelope with postage included. As long as these important pieces of wedding etiquette are adhered to, you can be as unique and nonconforming as you like with the rest of the invitation.