Use “-ize” verb endings, and related “-ization” noun endings.
Examples: organize, organization; realize, realization; nationalize, nationalization; utilize,utilization; emphasize; maximize; minimize; optimize and so forth.
Exceptions: advertise, advise, analyse, catalyse, comprise, demise, despise, paralyse, revise, surprise, televise
* Indicates a change from previous practice.
** Indicates an exception to the twelfth edition of the Concise Oxford English Dictionary.
* ** Indicates both a change from previous practice and an exception to the twelfth edition.