I could not think of any other hobby that is so multi-disciplinary and multi-facet. Could you? Come to think of it, even at the most basic level, this hobby involves some conceptualization and design work, carpentry, electrical and electronics, mechanical works, landscaping and painting and etc.
I have quite some reference books from my earlier days of planning for a US-based layout but have since acquired some German railway books (it also helped me to improve my Deutsch). With my new Billy shelf, I have now a proper place for my books and within easy reach. As I am also working for the railway but in the IT division, I have regular access to trade magazines and journals. These materials are useful if you want to follow some of the prototypical practices. I still find these materials helpful even though I am adopting and adapting Oliver Bachmeier’s trackplan. The idea is not to replicate what Oliver has done but rather a reinterpretation of his work. I like his trackplan within a compact space of 2,3m by 1,0m that I have (2 IKEA IVAR frames). He has also managed to fit in a staging yard and a helix at a lower level. This makes the operation of the layout more interesting rather than just trains running in ovals.
I do not limit myself to any single source but to learn and adapt from others including fellow modellers in other scales. Model railroad exhibitions are excellent sources of inspirations. Whenever you run out of ideas what to do to your layout, go visit others and get inspired. Here are some of the photos from the exhibitions that I have visited. I hope they will inspire you.
My model railroad toolkit – readily-available reference materials