This quick tutorial is primarily for my beginning sewing students, but it's a basic reference for a quick method of making two half square triangles (HST).
I'm a visual person, so I hope the photos help. If not, I'll do my best to describe what I'm doing in each step.
1. Cut (60) 5" or 7" squares from each of your two fabrics. 5" squares will yield a baby quilt and 7" will yield a large throw quilt.
2. On the WRONG SIDE of the lighter fabric draw a diagonal line on all 60 squares (On my squares, I drew on the gray fabric).
3. Pair up your fabrics and put them right side together. For my quilt, I paired a yellow/green with the gray. Line up your diagonal line with the edge of your pressed foot and sew a 1/4" seam line down one side. Don't clip the thread between fabric pairs (this is called chain piecing and it makes quilting so much faster). You should end up with a long chain of squares with one diagonal seam.
4. Take your squares out of the machine and flip them around, so you can sew a 1/4" seam on the other side. If you look at the squares in the photo, you'll see two seams on the same pair of squares.
5. Clip the thread between the pairs of squares and you should end up with 60 sewn pairs that look like this.
6. Before you cut your fabric, make sure you've sewn your blocks correctly (see step 7 for what your blocks should lookn like). Using your rotary cutter and ruler or a pair of fabric scissors, cut along your drawn line. You should end up with 120 triangle blocks.
7. When you open up your triangles, it should look like this. Press your squares towards the darker fabric. If your fabrics are similar value, pick one fabric and press all the squares the same way.