As you might know the new XPages design element of Notes/Domino 8.5 is based on a Sun Java technology called Java Server Faces or JSF for short. As such many techniques from JSF development can be reused in XPage development why it might be beneficial for you to follow some of the JSF litterature as well.
As always the newsletters from Sun is a good place to start and just recently there was two articles on composite UI components in JSF. You can find part 1 and part 2 on the web.
Update (4 Dec 2008): Corrected typo from “Java Server Pages” to “Java Server Faces”.
lekkimworld.com 
@Mikkel:
Amen! The JSF technology now in the Domino product will allow us to create functionality previously thought impossible in our product offerings, and XPages are a great entry-point for Lotus Notes and Domino Developers to start understanding OOP and Java by allowing them to use more familiar skillsets.
They did a great job with the “phase 1” implementation of this technology in the Lotus Domino product (despite a few RAD UI hiccups in the DDE client), and I’m really looking forward to mass adoption!
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Hi Mikkel,
probably you mean Java Server Faces or JSF instead of Java Server Pages or JSF 😉
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I do. Thanks! (will edit post)
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FYI:
I’m currently writing a blog series about leveraging the JSF features in XPages.
You can find it in our blog at
<a href="http://www.mindoo.com">http://www.mindoo.com</a>
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