What can I improve on?(singing)?

I really want to improve on my singing and by that I mean making youtube videos and having the right.presence. I don't want to seem nervous on camera and I really have to get better equipment to film and record myself on. I recorded this video on my iPhone and added the audio soundtrack separately.

You'll notice two things immediately the UGLY black bars on the sides of the video and how I come in off-tune on the "What would I do". I didn't play music in the background at all while I was filming this video because I didn't want it to sound like an ugly echo. I think that really messed up my timing. What kind of things can you do to solve this problem. I'm trying be more professional. All in all I just need tips on pretty much everything. Including vocals because I know I'm not the best that and that there's ALWAYS room for improvement any help at all is good!

Including critical feedback.

Added (1). @T I think I naturally sing with a lot of vibrato but, that is something I can definitely work on!

Your voice is shaking, stay still
if anything, have the music in headphones in your ear, if you don't want the echo.
don't be as shy, just go for it
tune yourself to make sure your not too sharp or flat

Your good to go