List all your property.
List all potential beneficiaries.
Do a rough matching.
Ask and answer as many what if questions as you can think of, both about the people and property. What if various people die in various orders before you? What if you dispose of property? What if you acquire more?
Work out a beneficiary for the residual clause for all property unassigned.
Think about whether the will is likely to cause upset and dispute, if so avoid it because your testamentary intention will be defeated if the will is contested and lawyers take all you have to give.
Take this material to a solicitor. Beware of wills kits and backs of envelopes. Your family will not thank you if you leave something ambiguous or unstated.
Solicitors will inevitably think of more things that you have not thought of. That is why you pay them. A good solicitor will draft a will to avoid ambiguity and will know the precise meaning of words like “”issue”, “”children” and so on. A will need not be full of legal mumbo jumbo. It can and should be in plain language.
A solicitor will also advise on family obligations that the courts will insist on anyway. You cannot always cut someone out.
Regularly review the will with changed circumstances.