Cool! I like the fact that you titled it mistakes that you make, rather than concentrating on things that you see your teammates do wrong (even though there was a little bit of that in the video). And I think you're right: many of those things you mentioned—warding, objectives, positioning—are good things to be aware of if you want to move up a couple divisions.
I think it could have been a little better if you had used in-game footage, though. Even if it was just an empty custom game where you moved the camera around to show the parts of the map you're talking about, it would have been easier to point things out. Dots and lines on a fully zoomed-out map don't do a whole lot to really show what you mean. Hope to see some more LoL videos from you soon!