Is there an online archive or database that collects seminal texts and articles for your field in history? Say I wanted to dive into reading on American immigration in the late 19th and early 20th centuries. Where would I turn to for reading beyond simply random googling for disparate texts? How do I find out about newly published work when it comes out in the field, or which journals to subscribe to? I know somewhat about the importance of H Net, but also don't know exactly how to navigate it.
One way of finding new books/articles that I use is Google Scholar. I would search for a book that I know is/was a significant contribution to the field, then click on the option 'Cited by' and then look through the results and filter by dates.
Once you have found something worth checking out, you can then check their bibliography and find further texts/articles that maybe have not shown up in your search.
Book reviews in journals are a good way to find out about new books. If you are a college student or live near a college and can use their library computers, you can get access to journals on jstor or Project Muse. Try Reviews in American History for a broad view of what's new.
To find older important works, read the footnotes of books you already know. There should be some mention of how their work fits in the historiography, especially in the introduction and its footnotes.