I've reviewed hundreds of junior portfolios and the same gaps keep showing up. Here are three that separate average from exceptional:

1. Spacing rhythm

Most juniors eyeball spacing. Seniors use a consistent spacing scale (4px, 8px, 16px, 24px, 32px). Your eye can always tell the difference, even if you can't explain why.

2. Typography hierarchy

Not just font sizes — it's the combination of weight, size, color, and letter-spacing that creates clear levels. If you're only changing font size, you're leaving half the toolkit on the table.

3. Color restraint

Juniors reach for 8+ colors. Seniors build entire interfaces with 2-3 carefully chosen ones plus their tints and shades. Less color = more sophistication = more trust.

I break down stuff like this every week at The Layout. It's free — come learn.