Well, there's a couple different things that factor into any accent. These include things such as pitch, intonation, pronunciation, and rate of speech. I mean rate of speech within a sentence, as well as overall, though that's more of a matter of sounding natural as opposed to having an accent. For example, some vowel sounds should be held a bit longer than the way the same vowel is pronounced in another word.
So there's a lot of different little things that contribute to having an accent.
Your pronunciation seems pretty good to me! I think it's more of a matter of intonation.
Listen and practice! Ask for feedback. Ask people for their own recordings of the same sentences. Write little arrows or dashes above Korean text to notate the intonation for yourself. Try children's audiobooks. Pay attention to what is being said, the context, the mood, the tone, etc of the text and audio. Try and pick out patterns. Listen to words in isolation. Listen to the same words used in several other common sentences and structures.
Your pronunciation of 공부 sounded a bit odd to me, but I'm not a native. I see you have two "natural" results for that recording as well :)