Q:

How to say "I look" as in "I look stupid" in French?

How do you say "I look" as in "I look pretty/stupid/etc"? Do you use ressemble?
Also, out of topic: how do you say "you seem adjective", and how do you express "pretty" as in "That's pretty dumb"?

A:

"To look" + adjective in French can be said a couple different ways.

"Avoir l'air______", e.g. "J'ai l'air ridicule."
"Paraître______" e.g. "Elle paraît fatiguée."
"Sembler______" e.g. "Ça semble intéressant !"

"pretty" can be said a few different ways as well, depending on the context.

"Plutôt"
"Assez"

are the most commonly used.
For your examples, you could say:

"J'ai l'air plutôt ridicule."
"Elle paraît assez fatiguée."
"Ça semble plutôt/assez intéressant !"

