What is the approximate value of physical assets (e.g., machinery, land, livestock)?
What level of debt is attached to it?
What kind of annual turnover has it had each year for the last five years?
What kind of income is projected for the next five years?
Are there any outstanding tax liabilities?
What threats and opportunities face the business?

These kinds of questions are relevant for the current business owner to consider before they enter into any discussions with potential business partners. You have to know thoroughly what you have before you can think about bringing family members or business partners in as they should be fully aware of the business's current financial position and prospects before becoming engaged in it, just like it would be if they bought a business from someone else. 

I always recommend that people talk to an accountant to get a clear picture of their current financial position, considering carefully issues like cashflow, equity, and debt.

Know your business' day-to-day management requirements
Most business owners have a general idea of what needs to happen on a day to day basis to keep their business running.  However, when considering succession, it is important to more carefully evaluate exactly what you do for the business every week, month, year etc. and what may be currently being done by staff or hired services.  For example, if you run a cattle property, someone has to be checking on feed levels, water supply and condition of the cattle, mustering, branding, and maintaining physical infrastructure and equipment on the property.  However, there is also the back office side of things like who is organising the buying, selling and transport of stock, compiling the Business Activity Statements, and paying the bills.  That's before you consider any advertising or marketing of your products or self-education into improving the quality of your herd (e.g., genetics) or your way of managing livestock (e.g., planting leucaena, feedlotting).  Who is looking out for new opportunities which may improve your business' bottom line?  

Often, when business owners carefully evaluate what they actually do every year for their business, they realise a whole range of things which they do almost unconsciously and which must also be handed over if the business is to succeed.