I drove a roll-off truck for about 3-4 years, I loved it, except the company I worked for at the time didn't give raises so I left.
I used the hand controls when there were overhead obstacles. Watch out
pr powerlines and trees!
Try to line up with the can from the get go, it'll make things easier! If you are not sure if the rails are lined up get out and look. When you get some experience, you can be a little off and still be able to pull a can on by steering under it.
I used to always let the cable pull the truck under the can whenever I could, especially when the can was stuck in the ground from setting for a while.
If you are trying to pull a can on and can't get it lined up because the ground is un level, don't be afraid to pull the can out from its spot. You can use the cable as a winch.
When your rolling a can off, you can set the back of the can where you want it and let the truck roll out from under it, sometimes.
You can back a can like a trailer to save time. tighten the cable to where the front wheels are off of the ground and back it in to your spot, just watch out for curbs!
There's some info to get you started.