The stuff nobody tells you about fit isn't about the mirror—it's about how the tee behaves in real life.

• Check the sleeve length. On a regular fit, the sleeve should hit mid-bicep. On an oversized fit, it should hit just above the elbow. Anything longer makes your arms look shorter.
• Look at the shoulder seam. For regular, it should sit right at the edge of your shoulder bone. For oversized, it can drop an inch or two past—that's the point. But if it drops more than two inches, you look like you borrowed it.
• Test the hem. Regular fit: tuck it or leave it, both work. Oversized: leave it untucked, and make sure it falls around the hip—not past your crotch, unless that's your thing.
• Consider the fabric weight. Heavier cotton (around 6 oz) holds its shape better in an oversized cut. Lighter fabric drapes and can cling to your midsection, which defeats the purpose.