Read, read, read! That's the best advice I can possibly give you. Read scholarly text, read books on historical methods and theories, soak up as much as you can and why not try to apply it here in this very subreddit? Check out our Monday Methods and Theory Thursday features!

A crucial first step would be to actively continue reading. Exactly what you should read depends a lot on your areas of interest, but I'm sure the folks here are happy to give recommendations. Getting your hands on the books/articles themselves does not necessarily involve debt. Some suggestions:

• Are you still living near your former university? Does your ID or login credentials still work? If so, you have a wealth of library resources at your disposal. Many sizeable universities also purchase subscriptions to large resources like ProQuest or JSTOR, where you could find many articles/book reviews. (Edit: if your credentials still work you can probably access a lot of materials remotely)

• Don't live near your old uni? Do you live near any state schools? State universities often make their library resources available to any legal resident of that state, as they are a public institution. I do not know if this is true for non-US universities.

• Don't live near any universities you can access? Is there a local library? If so, check out their interlibrary loan (ILL) options. Many libraries have participate in sharing programs where they'll locate the books you want and have them brought (temporarily) to your local library.

• Some online courses are out there for free, like this one. It's hard to complain about a free course on the American Civil War era taught by Eric-freaking-Foner.

• Subscriptions to various historical journals would give you access to recent research and book reviews, but it's unfortunately NOT FREE. Rates vary depending on the organization and your professional status, and again, I'm sure the community here would be happy to recommend journals.