The only thing I would add to this well-structured approach is to emphasise your achievements rather than just listing your responsibilities.
I would also note that with 18 years at a single employer it is important to separate out each job you have held over the years, describe each one and list your accomplishments and achievements and how you moved to the next set of responsibilities or how your job changed over time.
This will make it easier for your prospective employer to see the development of your abilities over time and make you comparable to others who have switched employers and jobs.
Before you are even called for an interview, start asking friends who hire for their organisations to conduct practice interviews using the job descriptions for positions that you are applying for.
Ask them to ask you difficult questions and give you honest feedback on your responses.
In your own preparations, you should be aware that many employers have been trained in "behavioural interviewing".
This means they are looking for examples of past behaviour that allow them to gauge whether you have the required skills and abilities.
For example, if they are interested in teamwork, they might ask you for examples of situations where you have been a team leader or member of a team and then ask you questions about your role, contribution, and how you resolved any problems.
You can prepare for this by carefully reviewing the job description and advertisement to identify desired skills and characteristics and thinking about examples you could discuss in an interview that demonstrate you do have what they are looking for.
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