As well as obvious things, such as: the physical, financial and data security, you should ensure that you have good IT and internet security; plus the necessary (including Cyber) insurance. It also makes sense to have a solid Business Continuity Plan.
The structure of your business
Limited liability: Trading through a Limited Company (or an LLP) means that your personal assets – home, savings etc. – are protected if your business goes bust. For many businesses Limited Liability would be absolutely vital.
Limitations of Limited Liability: Although personal assets are protected, in the event of your Company failing; if the tools of your trade are owned by your Company it can mean that you will lose them and possibly your livelihood. However, if buildings, vehicles, plant – are owned by you personally and rented to your Company, you can still keep your trading assets.
Share structure: It is often tempting to set up a Company’s share ownership structure in the most tax efficient way – and accountants earn their money doing this for their clients. However, it is important to remember that shares mean votes and control (not just dividends) so giving away shares to save tax may ultimately prove a lot more costly than any tax savings if shareholders fall out with each other.