Do guys take notes in class?
what do you recommend? is it waste of time?
I don't know what your education system is and whether you are supposed to take notes or it is a matter of your choice. When I went to school and later to the university in Russia, all the students took notes (except those who didn't care about their studies at all). These concise notes were much more helpful than large textbooks with too much information to filter out.
It is also important to know which type of memory works best for you. Some people remember things better when they read, others when they listen, and some when they write. If you belong to the third group (like I do, for example), you'll remember more if you take notes. I wrote something when I prepared to exams using my own notes or textbooks. I had to write formulas and draw graphs just because it was the best way for me to remember.
I think it depends upon your learning style. For me, writing something down by hand is the surest way to get it into memory, or straighten out concepts I'm fuzzy on. If I need to memorize something, say irregular verbs, the best way for me to do so is to write it out a few times. The more different techniques I use to study, the more little connections I create in my brain, the more likely I am to be able to recall the information I need, so in the case of languages I also make a point of doing translations and listening and applying it however else possible. Speaking the language with someone who speaks it fluently and could coach me on little nuances or slang would probably be even more helpful, but I haven't done that yet.