I learned to pull threads to get a straight line and then cut, but I will only do that on a courser weaver. Tear if I can

That's what I do as well, and so far, no wonky strips, so I must be doing something right. I was originally taught to pull a thread from near the edge, but found it time consuming and not much help if the print is off the grain.

If you're having difficulty with holding the fabric up, if you have a large enough flat surface, match up your selvage edges, lay the piece on the table and smooth the two layers from the fold to the selvage. Your edges will likely be mis-aligned at that point but you'll have the fabric straight. You could probably use a couple of pins on the fold edge to hold things in place if it's a large piece. I find doing the 'thread pull' technique very tedious with the cottons we use for quilting.

You could also try just working the loose threads from one cut end until you get all the way across the WOF. Line up those edges and that will give you straight of grain as well. At least that process you could sit for!

What I do is tearing the fabric an inch or two from the side. Then I fold the fabric so the selvages are on top of each other and the torn edge is exactly aligned. Then I press a new center fold in the fabric, by going from the selvage to the middle of the fabric, making sure the fabric is lying flat. To make it easier, you can pin along the selvages to make sure the fabric won't shift there. You end up with a new center fold and fabric that's on grain, ready to cut into strips.

I hope that made sense, it's easier to do than explain in words.

Sheri, this is how I was taught to do it also, in JR HIgh sewing class. Also, in high school sewing class, the teacher had two of us take diagonal corners and slightly pull the fabric, working toward the center. This also helped to straighten the fabric.