I agree with the thumb on the tension trick. I've done that for years.
Here's a little trick that has helped me many times. I have quite the variety of machines, especially vintage machines, and rather than try to remember, for each machine, whether the flat of the needle goes to the left, right, or back, I have a tool. That tool is a dental mirror, which you can get at many drug stores. Just hold it under the empty needle hole, and you know immediately.
And speaking of needles, I find it most helpful to have a small plastic needle inserter to position and lift the needle into place and hold it while I tighten the screw.
If the dental mirror comes with a tool with a thin hook used to get between teeth, lucky you. You can use it to pull up the loop of the thread after inserting a new bobbin. It also works well when free motion quilting and you need to pull the thread to the top.