I cannot stress enough the importance of making sure your kit is in order. Speak to your solicitor and accountant and prepare for the sale ensuring all your documentation is up together. If there are any problem areas in the business these ought to come to light now and be dealt with prior to the business being marketed for sale.
Build a team of advisors around you that you can work with. A commercial solicitor, accountant, tax advisor and broker/agent will of course be key to this.
Discuss the deal with your advisors and be clear on who will do what and when. Differentiate your business opportunity from that of others – finance your sale in such a way that it is attractive to prospective purchasers and beneficial to you from a tax point of view.