Coach Ken Eriksen demonstrates the best technique for runners that have effectively hit a ground ball through the infield, and therefore have the opportunity to run to second or third base.
The runner creates a rounding motion through first base and can then create a sharper angle to get to second or third base. If you want to maximize speed, it's important for the runner to contact the first base with the right foot so she can then create a sharper angle to get to second or third base. However, it's important that the runner keeps her base options open by not creating too direct of a line to second base. There should still be curvature through the run so she is able to make it third base, if possible.