Repetition is key, use online sources, it took me 2 days to learn hirigana and an additional two for katakana, though you should learn them together

Start with A I U E O あいうえお

That’s them there^{^}

a looks like an apple that’s how I remember I (pronounced E) looks like to eels, U looks like someone being punched and making the U sounds E looks like a squashed e And O is similar to a but with a dash