Pitch accent in japanese

There aren’t many ready made rules for pitch accent, which is what you’re talking about. There are a couple of patterns that are possible (4 if I’m not mistaken), and each word has one (or just to make it more fun, more) of these that applies to them. There are some patterns for groups of words that at least let you eliminate them in a batch, but it’s pretty much a per-word study thing. The even sadder thing is that this all depends on where exactly in Japan someone is, though I’d assume that there’s a set for standard Japanese, that would be a good starting point.

If you are really serious about it, it’s something that basically needs to be memorized alongside the words, not unlike their ichidan-godanness.
Dictionaries have about a dozen ways to show this pitch accent, the 2 most common I personally know are these sort of diagrams:

But in some cases you might just get an index or name of the pattern you need to apply to the word.

I personally don’t (yet) worry about this myself, but I’d honestly try to internalize the forms these can take and then it will be easier to categorize each word in your head.

Wanikani has a few scripts that lets you study the vocab words it gives you with the pitch accent, for example:

Also, there’s Dogen’s youtube channel who specializes in this, and runs a pretty popular series (though you will need to pay for his patreon to get the full thing).

I personally wouldn’t yet worry, it’s not something, that you need to learn if you want to be understood, unlike sheer vocabulary and grammar, but if you’ve got the time, don’t let me stop you.