Here is a technique (I wish I was clever enough to have thought of it myself) that will give you very good results.
Cut your squares out of 2 different fabrics on the straight edge (parallel to the selvage edge). Layer 2 squares together, 1 of each fabric, with right sides facing. Make edges match. Draw a line diagonally (on the bias).
Stitch 1/4" on either side of your drawn line. When making several triangles just add the next square in line so that you are stitching several in a single line and not stopping after each square.
Then separate your squares and cut down each one on your drawn line.
Then open your squares and press. Ta Da!
And so why am I blogging about making triangles? Well it is to show you my bias rolled petal two-toned rose of course!