It helped me a lot to just listen to the words A LOT, repeat them out loud, then listen again to see how close I was to native speech. Listening and then repeating is key.
One thing that helps is to notice that pitch accents vary a lot according to regional dialects. In fact, it’s one the main distinctions between dialects. So if you are watching dramas, for example, pay attention to which regions the characters are from, and how that affects their accents.
As you probably already know, Tokyo accent is relatively flat, and pitch accent is deemphasized. This is especially true of people who moved to Tokyo as adults for work, who may overcompensate trying to fit in.
Your perception of pitch accent would depend greatly on your native language, so there is no one size fits all solution IMO. Personally, I did not find all that talk about the 4 pitch accent patterns and which syllables are H and which are L all that productive. However something that may work, and what helped me come to grips with this, is thinking of pitch accent in terms of stressed syllable. The stressed syllable would be the one right before the fall in pitch. So in atamadaka the first syllable is always stressed, with nakadaka and odaka you get a gradual rise toward the stressed syllable (in odaka it would be the final syllable), and a fall afterward. And then heiban is truly flat since it has nowhere to rise to and no fall -- you just try to start high and stay that way until there's some other word that would have a stress on some syllable.
BTW, yomitan has a great pitch accent dictionary available, so quite often I try to guess where the stressed syllable would be in a word (I don't really know any rules, but there are definitely patterns you can take advantage of), and then check with yomitan if it's correct. When I'm not lazy, that is -- unfortunately, I'm not up to making a concerted effort to memorize all these stresses.
I struggled a lot with the pitch accent quizzes (even if I could imitate pitch accent when saying words out loud) until I learned the basic rules and patterns of pitch accent. Once I understood those, it became easier to recognize the pitch patterns in the words I was learning/quizzing on. I still struggle with the おだか「尾高」pitch pattern (when pitch drops AFTER the word) but I don't worry too much about if I misidentify those as the へいばん「平板」pitch pattern (when pitch stays high after the word). But knowing these things definitely helped, and the more words I learn pitch accent on, the easier it is to recognize the pattern, and even predict what the pattern will be.
Here's a good video to learn the pitch patterns and rules, from Speak Japanese Naturally on YouTube.
Hope it helps!
EDIT: Also, I have "play pronunciation after answering a question" turned on in the quizzing settings so I hear the words as often as possible, and say the words aloud (or in my head) when I quiz on them (even if it's quizzing on writing them) to check my pronunciation/pitch accent, and then say it aloud/in my head correctly after if I got it wrong.
Also, I would not think of pitch accent as stress. It is actually rise and fall in pitch (high/low) of mora in words, rather than stressing syllables as in English, where syllables are voiced with more or less force.
I tried different pitch dictionaries, but for me personally, watching anime and following some Japanese bloggers, who are teaching foreigners Japanese words/sentences, are the best choices. I’m kinda a visual learner, and it is the easiest way for me to learn when there is some vivid information. Anime is vivid, rapid, sometimes kinda exaggerating, I pick up a lot from watching it. And for those Japanese bloggers/influencers, I follow them on instagram, tiktok and youtube, they usually provide information with little action scenes — funny or just interesting, and it really works for me
