Hi theyleaveshadows! admin ʀ here~
Writing translyrics is a creative process and like all creative processes, you are bound to whatever boundaries you set for yourself. No one but you sets the rules on how or what you should be writing.
A "good" way or a "bad" way is subjective to the reader/writer, so I shouldn't be dictating to you how you should go about writing your translyrics. That would only hinder your own individual creativity and style.
I will however leave you with a few questions that may help you set up some boundaries for yourself so you can create your own style:
Are you aiming to convey the original meaning of the song (including the metaphors) or just convey it in your own words?
Do you want to literally translate it down to every single word or are you okay with paraphrasing it to give a gist of the original meaning?
Do you want to strictly follow the syllable count?
Are you okay with adding extra words if there aren't enough syllables?
Do you want to keep it in the original melody?
Those are only a few questions I can come up with at the moment. Of course, there are many more but this should give you an idea of what you need to do to come up with your own way of writing translyrics.
If you have trouble understanding a song, I suggest that you look through several different translations (not all translations are accurate or grammatically correct!) or ask a Japanese-speaking friend for help. Some songs may also require you to do some research to fully understand: for my own set of Romeo and Cinderella lyrics, I had to look up some fairy-tales to understand their context in the song.
The level of difficulty in writing translyrics is really up to how much effort you want to put into what you write.
Hope this helps! admin ʀ