Feets brings up many good points.

Keep them under 20 minutes.
Cell phone audio is [censored] at best, get a good microphone. Cell phone video is okay to start with but invest in a Camera and tri pod when you can.
You should do the same task multi pal times from different angles/perspective and edit them so they flow as one.
Editing will take you three times as long as filming.
Watch a bunch of videos on the subject you are planning to do to see how they are, and what you would do to improve them.
If you want to make money from YouTube, you will need to get many likes and subscribers, so don't forget to ask your audience to hit those buttons.
YouTube tracks, when people do not watch your video all the way through or fast forward them, and docs you for it.

Good luck with your adventure! And make sure you are having fun doing it, the audience can tell.