This is a suggestion that might get people interested, but, first, are any of them 1st time cruisers? do you have a line in mind?
Invite your family & friends to a cruise cocktail party! You could make a bon voyage invitiation on your computer,and invite your group, to a casual party, to chat about cruising.
See if the line your preferred line has any video's available,and get some cruise brochures for everyone to look at. You could gather a few line's brochures, for options as well.
Go to the Dollar store and see if they have any inexpensive travel decorations & any festive tropical glasses,to serve Caribbean drinks, to get people in the mood
Do your research,so you may be able to answer questions like, but I get seasick..Bam, you'll have the answer
Call your cruise travel specialist,and let them know when you want to cruise,an they can steer you to the best values. Let them know that they can make payments on the cruise too.
Be enthusiastic,which we all know is not hard to do when we strart chatting about cruising,and I bet it's contageous. Let us know if you need any help,and let us know how you made out...good luck!