How to constrain resizing in blender?

When I am scaling two or more vertices, they scale so quickly that I am not able to control properly how much I want to scale. Any way to control this function?
Moving is not a problem. Scaling is. The object just becomes REALLY big really quickly.

Hold Shift key down when moving the mouse or move the mouse cursor further away from the vertices before you start scaling

Also try placing your mouse cursor farther away from the vertices before hitting S. The closer the mouse is to the affected vertices when doing transformations, the more ‘weight’ your mouse input has on the transformation.

I agree with what both said, though I’ll add that you can constrain the scaling by not only the shift key, but also with the CTRL key as well as the combination of both the CTRL and SHIFT keys. Each constrains to different units, giving you some flexibility in the control. Also, if you know how much you want to scale (0.5x, 2x, 3x, etc) you can type in that number to explicitly state how far you want to scale.

Just tested on my “Default” scene, and on mine, CTRL scaled by tenths (0.1), and CTRL+SHIFT scaled by hundredths (0.01).