I'm a huge fan of double entry accounting, regardless of vessel (I do it in Google Sheets from time to time), even for the simplest things. Very flexible and powerful, yet safe.
Also, Fava adds budgeting to Beancount. Beancount itself doesn't really have the concept, but Fava lets you add budget lines and compare your spending against your budget.
And the links from there are a pretty good start. Start with just basic asset tracking (checking, savings) and liability tracking (debt, CC) and get into the routine of it. Then you can add in your investments and other assets (car, home, stocks, foreign currency holdings, etc.). If you don't care about a slightly inaccurate history, just add the stocks later on at their present value, or go back and find your initial purchase dates and cost basis and let ledger calculate your present gain/loss.
https://www.ledger-cli.org/