I don't rip as I think it distorts the fibers where ripped and there could be some fabric loss if trimming to get to undistorted threads.
I fold the fabric selvage to selvage and then hold it up horizontally. I shift the selvages between my fingers until there are no "wrinkles" or appearance of shift of fabric to the left or the right. When done, the fabric appears to be hanging straight down to the fold. This usually works well but then I usually add this step:
I continue to hold the selvages together in one spot with one hand, as per above step, and grab the fold in the other hand and then hang the fabric vertically. If the selvages meet down the length of the fabric, I'm golden. If not, I do a little more shifting of the selvages until they meet. Once I've done this, I continue to hold the selvage as earlier and then shift my hand holding the fold to another point on the selvage and lay the fabric on my cutting table.
Hope this is clear and that it helps. Let me know if it's not clear.
Cathy
ETA: If the fabric length is longer than I can hold, I will fold it in half holding it in the center point and examine the meeting of the selvages on both sides.
ETA2: What Neesie says. I always perform the above steps after washing.
ETA3: Sorry folks...I think this is an important step as cutting "off-grain" results in more fraying - IMHO.
I promise - done now.
