There is an oft overlooked grammar particularity that the average gaijin ought to know about this ubiquitous near-expletive word of the Japanese language lest some serious faux pas be made.
Among the first things one learn in Japanese grammar is the possibility to give straight adjectives a layer of "perception" by appending the suffix sou (pronounced "so" with a long "o" which the standardized romaji spelling writes "ou"). I think this is technically called a "hearsay adjunct" in serious books (maybe "likeliness/appearance adjunct" would be more appropiate - thanks JudyT).
korewa oishii ("This is delicious")
korewa oishisou ("This looks delicious")
korewa muzukashii ("This is difficult")
korewa muzukashisou ("This looks/sounds difficult")
It is however important to know that, although this construct works for nearly every adjective, it should not be used (unless you know exactly what you are doing) with kawaii...
Let me illustrate:
Picture a beautiful and mysterious burgeoning love in the land of the rising sun and the falling sakura leaves... made more than a little awkward by the shared inability of these two lovebirds to comprehend much of each other's language.
Now, picture this young stupid and innocent gaijin striving hard to compliment his girlfriend on her look and particularly on some freshly bought uselessly cute piece of body ornamental crap that Japanese gross consumerism seems to thrive on.
Knowing the aforementioned facts about Japanese grammar, you might be tempted to risk a "this looks cute on you" (kawaisou !), right?
Well, this young lad was... And did...
And he had to spend quite a bit of time afterward trying to convince her that he never meant to say that she looked pitiable/pathetic, as, you guessed it, this is what kawaisou (可哀想) actually means in modern Japanese, due to some obscure remnant of the previous definition of the word (see write-up above).
Of course, such kind of cultural faux pas have been made by about anybody who ever set foot in a foreign country. But I just thought you might want to avoid this particular one, shall the occasion ever arise.