Recruit friends and family to go in on group rates for a cruise. Make sure that everyone is really interested as the rate will depend on quantity of passengers.
Decide on a date that everyone can accommodate. Make sure this date isn't around major holidays as it may end up being a reason for several cancellations. Have an alternate date in mind in case the first date isn't available.
Get price quotes from several travel agencies. Inform them of the size of your group and the dates your group wishes to take the cruise. Compare prices and accommodations to get the best deal.
Meet with a travel agent to book a cruise. Inform them that you are looking for group rates with the dates you have in mind.
Collect the down payment from your group. This will reserve the cruise. No one will be able to back out once the down payment is made without having someone else to take their place.
Make the final payment on the cruise. Call to make sure that everyone is attending. This will give you time to find a replacement for your group if someone is unable to take the cruise.