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Other notes
I have attached a template that I use at the moment. It illustrates some of type of slides that I use at the moment. It can be much better :).
I will not be using my slides to add lots of text. I will use it to present key takeaways in bullet format and also insert screenshots with some text as a title.
Even though clipart/icons can be cool I will not be going out looking for new icons for new presentations so I want icons included to be generic and reusable in most scenarios.
Also I will not be using any charts. It would be good however to have examples of good looking SmartArt that can be used for processes, lists and circles.
If you use fonts that require a license, confirm with the client they're ok with it. For licensing reasons, it is better to provide your client with information on how to acquire the font rather than providing the actual files.