Ok, I've read through almost every post on sewing problems and they have answered nearly all of my questions (thanks everyone!), but I have a quick one on thread tension.

I'm adjusting the top and bottom tension as described here, but when I finish a few inches of stitching, the threads still seem loose. If I push on each thread with a pencil point, they give a bit and I can pretty easily loop the pencil point under each stitch.

Should I increase the top and bottom tension until each stitch is tight? I know how to tell if the top tension is too tight or if the bottom tension is too tight, but how can you tell if both top and bottom are too tight?