Four-Patch Block Instructions
Here is a sample four patch block and some comments on construction:

As you can see, the Four Patch is a simple block.
The dimension is 6 1/2". For newbies to piecing, the technique of making the
strips oversize and then trimming down to a perfect 6 1/2" square will work
fine. Use one of the 6 1/2" plastic squares described above. Use the center
as your key when trimming... In making mine, I cut 4" strips instead of 3 1/2"...
joined with standard 1/4" seams... when finished and ironed, using a gridded
ruler and the center of the block as the key point, I trimmed trim each edge
3 1/4" out from the center. This is extra work, and wasteful of fabric, but
gives a perfect square even if your piecing isn't. This is a step I especially
like to take when I know my blocks are going to end up being matched with those
made by many other people. For those who piece precisely, ending up with an
exact size is not a problem, but for the rest of us, it insures that our blocks
won't be the ones that cause problems in the piecing of the quilt.
The orientation of the block is not critical, but just to keep everyone on the
same wavelength, let's say the muslin square should be NW. I had intended to
put my name in the NW corner and the machine info in the SW corner. Somehow,
when the blocks were finished, I felt all the information being in the NW corner
looked a little better. It isn't critical and there are always variations. Remember
that when mixed with the other blocks into some as yet unknown pattern, all
the blocks may end up in different orientations to emphasize color or pattern.