Hi
I do mine on a spreadsheet. I do it every 6 months at a time. I include treatment offers, gift voucher offers, events,what retail displays we will do that are relevent and also what we will put in our monthly email newsletter.
I also have some brainstorming with my staff and often they come up with some very good ideas.
I sometimes change things along the way if I need to. I then brief my staff about whats coming up so they can talk to their clients about what offers are coming up etc.
Hope this helps
xx