To scale edge loops in 3D models fast, use your software’s edge loop selection tool (e.g., Alt + right-click in Blender) to highlight the loop, then apply the scaling function (e.g., "S" key) while constraining the axis (e.g., Ctrl + X/Y/Z) to keep the model’s shape intact.
This method is fast because it targets precise edges and prevents unintended distortion—great for adjusting character features (like arm thickness) or hard-surface details (like product curves).
If you’re new, try practicing with a basic cylinder in Blender; memorizing shortcuts for edge loop selection and scaling will speed up your workflow with regular use.