The biggest barrier to entry for Contentful is switching from thinking in “Pages” to thinking in terms of structured content types that are composed together to create those pages.
Any application on the internet can be modelled in Contentful by decomposition and abstraction. That may be a useful exercise. A web page is simply a (Container) for its constituent parts, which simplified look something like:
Accepts one or more (Banner) types which are (Image), (Overlay Text), (URL)
Accepts one or more (Product) types which are …
(Footer) which contains one or more (Link) types
You get the picture. Doing this exercise on a whiteboard in conjunction with an IA/UX specialist will really help you understand the content model required.
The hardest part of Contentful in my opinion (when applied to web sites) is the creation and management of the navigation path through that site. It can get really complex when you have non-simple use cases like non-uniform journeys, orphan pages, pages with multiple entry routes etc and ends up getting managed separately. Arguably a good IA should simplify this before implementation, but it’s not always possible…