Tips for movie making?

Years ago I moved from P&S to DSLR because it enabled me to make pictures I found hard to do with a P&S. I got good tips from others, including this forum, which really helped me climb the learning curve. Thanks for that.
Now I'd like to do the same for video: creative movies, shallow DOF, video composition & lighting, etc...  Replacing the 300D and handycam by a 650D seemed an obvious move. I do not expect auto-mode P&S handycam behavior from the 650D as I did not expect P&S snapshots from the 300D that went before it. However I do expect good video footage out if it, provided I do it properly and it seems to be more than adequately equipped. So obviously I could use some tips again to make conscious decisions regarding the camera settings and use.

So far I'm pretty impressed with the new Hybrid AF combined with the 18-135 STM and already found ways to put it to good use like:
- precise pre-shot touch focus (steady frame, fixed focus), 
- how to temporarily AF during recording without hunting (flash button, center AF point),
- 1/30" shutter for running water.

However I am not sure how to make the most out of the M mode for movies... 
Who wants to share his/her tips & experiences?