Mantiz>>> I feel it is a good shot since you mentioned it is your first time. Got to start somewhere and got to get dirty, only then, I believe we can better ourselves and learn.

Coming from a newbie in videography.
1. The lighting, especially, when the singers walking. It was quite good. I really love the lighting in the part where the guy playing the cajun.
2. The colours are full. Not over-saturated.
3. Sharpness. What can I say, you are using 5DM3.
1. Further develop the "journey" for the girl and the boy to meet up. In the video, the "journey" was not really develop. You can just make the girl walking down the stairs of the house, going outside to get reception and end up at the very spot where she is standing at the end in the video. Same goes for the guy.
2. Framing wise, try to mix it up. You need to move the audience, in a way. My only pointers dun try to cut your subjects at the joints, like shoulder,neck, elbow, knee. Usually mid shot, try not to cut headroom. If you are doing close up, headroom can be cut but not the chin area.
3. Try to finish up your shot. Example, you were focusing the guy playing the cajun then you want to rack focus into the guitar. Just when the guitar wanting to get focused, you cut it away.
Noted bro, I'm thinking to shoot without lights at all next time since we reshooting; since the mark 3 seems to be able to perform well under low light ^^
- A BIG NO NO!! Even you are shooting with 5DM3, you still need the lights!!!!
I am also on a learning journey in videography. My inputs are merely from my learning mistakes and from people who have pointed them out to me. I am just sharing. I am no real pro. Overall, your video is technically better than mine. Good Job!!
Anyway, you might want to take a look this video about framing.
HFSS Episode #5: Framing for Film on Vimeo