Choose a key before copying the original
The original key may not fit your range. Use Piano to check whether the lowest and highest notes are comfortable before deciding whether to transpose.
When practicing a song, do not only sing it from top to bottom. First check whether the range fits, then isolate hard phrases, endings, breaths, and tone.
First find a comfortable key, identify the highest note and longest phrase, then loop difficult 2 to 4 bar segments. Check pitch, breath, resonance, and endings separately instead of singing from top to bottom.
The original key may not fit your range. Use Piano to check whether the lowest and highest notes are comfortable before deciding whether to transpose.
The hard part is rarely the whole song. It is often one high note, long phrase, turn, or ending. Fix one at a time.
The useful question is where you get stuck: which note, which phrase, or which breath. Marking those spots helps more than rereading the whole lyric.
Use Piano to test core verse and chorus notes and decide whether to transpose.
Loop the hard phrase three times and see which syllable or note drifts.
Split the longest phrase in half, stabilize each half, then combine.
When the chorus gets louder, check clarity so volume does not come from squeezing.
Sing long endings straight first, then decide whether to add controlled vibrato in the second half.
Yes, but practice should focus on range, phrase challenges, breathing points, and endings. You do not need full lyrics or notation for that work.
Full run-throughs are useful for checking progress. Improvement usually comes from looping short phrases, locating errors, and fixing one issue at a time.