Well, in terms of pitch, here are some tips that you can use to get better over time.
1) Warm Up: Do some vocal exercises before you start practicing and/or singing. Like stretching before playing sports, warming up your vocal chords and larynx properly will reduce the risk of injury. It can also relax and loosen your chords to make your voice flow better (if you get what I'm trying to say). Some techniques can even help with your range and vocal development!
As a simple warm up, you can hum lightly up and down the scales just to get ready. Lip trills can also help. I'm not exactly a genius, nor am I a vocal coach, so it would be best if you looked up some more.
2) Breath Support/Control: I don't know how you're breathing or where you're breathing from, but most professional and trained singers will probably tell you to breathe from your diaphragm. If you're doing it right, you're stomach should rise a bit, and you're shoulders shouldn't be moving upwards.
3) This next one isn't quite a singing tip, but in some parts of your cover, I noticed a static-ish sound. There are two pretty easy fixes to that. The first is, if you're using a microphone, turn down the gain. You can also try using the compression and EQ while mixing.
4) In a few of the parts, you sounded kind of unsure. Singing with more confidence will definitely improve the quality of the cover. That brings me to the last point.
5) Practice makes perfect. Practice the music, whether you block or find sheet music, until you think you've gotten it to 1000% of where it could be. Then go again. Even trained singers and popular utaite do this.
I hope this information was helpful to you. If you want any clarifications, or if you have more questions, please let me know!
thanks for this! I really need this info. so far I only feel like I was only able to smoothen the pitches I can't reach before but still hard to reach high pitches. thanks so much, though until now I haven't fully understood how to breathe properly.
oh thnks shiion-san
What do you think?