We all have different ways of organizing projects - not just models. For models, I usually collect images and text and drop them into a folder or bookmark pages. It works most of the time, but web pages can disappear or I can forget that I even saved them.
There are software options like OneNote (Microsoft has a free version) which works well, but the files and bookmarks are tied to the program - and Microsoft - unless you export them.
I recently tried
TiddlyWiki and it's a simple, browser based note collector/organizer. What's nice is that you really don't need a third party program or even a network connection to use the collected files. Saving from the browser isn't obvious (you have to follow their instructions) but it generates a single HTML file for each project that only needs a browser to read; if you add images, they're included in the file rather than scattered all over the web.