To be honest, I don't change the tension on my machine when I FMQ, I use my embroidery foot (which is probably the same as the darning foot), I don't adjust the tension, I do drop the feed dogs, and I do bring the bobbin thread up to the top.
The loops happened when your machine is going faster or slower than you are moving your fabric around. You have to find the speed that is right for you. If your machine is running at a slow pace, you must move your fabric at a slow pace. If your machine is running at a fast pace, you must move your fabric at a fast pace. Once you find your comfort level, your stitches will be even and non-loopy on the back.
To practice, I use the prequilted fabric. There's usually a piece or two really cheap in the remnant bin at the fabric store. I use contrasting thread so I can see my stitches clearly.