All very good advice!!
I think my first machine was a little prone to jams too, which caused some frustration but also built in a lot of these things you've listed as habits with me and now I almost never get jams on any machine.
When I'm removing work from under the needle I very gently pull and I can feel if it's still hooked on that last stitch. If it is I just rotate the wheel towards me until it lets go and I go just a scootch past that. I can see the last stitch sort of tighten up and look more "normal" when it releases that last loop too. Then I know I'm safe to pull a length of thread out and snip my work off.
I am also in the habit of dropping my presser foot back down on top of the threads before I snip. That keeps them from rebounding or falling down into the bobbin area, and keeps them neatly held to the left where I can sort of pin them down to the bed of the machine with my pinkie finger on my left hand as I'm placing the next bit of fabric under the needle. This way I always know where my tails are and they are kept to the side and are much less likely to create a nest.