Do I measure including the thread? Or do I measure from the side of the thread to the edge of the fabric?

I'm thinking based on how my blocks are coming out...it's the former.

I used an Omingrid ruler and line it up with the needle hitting the middle of the line. Then I place blue painter's tape along the edge. There are various ways of getting an accurate 1/4". You just have to find out which method works best for you.

Thanks but does the 1/4" include the thread? I'm not sure where to begin measuring.

I had no idea it could be this complicated! I guess, based on how my blocks are coming out (smaller than they should) that I should be including the thread in this case. What do you folks do, make a small test piece with the thread you will be using and see if the end result is the correct size?

The size of the finished piece is what matters, not necessarily the size of the seam allowance. It's just that if you cut accurately and sew with a scant 1/4", the finished piece SHOULD be the right size. Instead of trying to measure the seam, try sewing together 3 fairly short strips that are 2.5" wide. Now measure. The center strip should measure 2" (because 1/4" was taken away on each side) and the outer two pieces should each measure 2.25", for a total of 6.5". If the measurement is less, try sewing with a slightly smaller seam allowance; if more, then increase your seam allowance. If you change your thread you may have to repeat this process to find your perfect spot for sewing.

Here's a tutorial on how to check your 1/4" seam. That's how I check mine.
Yes, do a test piece with the same fabric and thread that you will use for your project.

http://www.seamstobeyouandme.com/201...rfect-14-seam/

When I started quilting again after a 10 year break I spent over and a hour just sewing together short 2.5" strips and measuring the result until I was sure I had the 1/4" seam process back in memory. I'd just recommend several iterations of practicing sewing a set of short strips like was mentioned above. I like to sew 3 or 4 strips together. If using 4 short (6") strips that gives you 3 seams. If your 1/4" if off each seam increases the problem. So with 3 seams you can more easily tell if you have it right.

Totally agree with the suggestions. It's not the part to the right of the needle that is important. It is the size of your piece after you sew and measure.

I don't know if it's so much what your seam measures as what your finished block measures. The amount of seam allowance can vary depending on what thread you're using. That's why test blocks are important.