To adjust a frame's size in Figma, use the Design panel on the right. This method is not only quick but also precise, ensuring your designs maintain balance and proportion. Here's how:

• Locate the W (Width) and H (Height) fields under the Frame section of the Design panel.
• Type in new values or click and drag horizontally over the input field's icon to adjust size dynamically. Dragging left shrinks and dragging right expands the frame.
• To maintain aspect ratio, click the icon on the right of the W and H fields. This locks proportions during resizing.

Remember, tweaking frame sizes tailors your canvas to fit diverse content, much like fitting a picture into the perfect frame.