When it comes to static stretching, the key is to make sure to use proper form to isolate & effectively target specific muscles or muscle groups. However, if you really want to maximize the impact and really increase your overall mobility, consider adding “reciprocal inhibition” (a contraction of the muscle opposite to the one you’re looking to stretch) to more effectively relax the target muscle which allows for a more complete stretch.
 

Here’s a video from Dr. Jason Lemieux of Physiomed Oakville that demonstrates how to incorporate reciprocal inhibition when static stretching key muscle groups: