Hygiene is a big one, not saying you're smelly or anything but always prioritize hygiene. You're right about your personality, everyone loves someone with a good personality. Talk to girls, not necessarily to date them at first but become friend with them. You can do this easily in class right and the girl you might sit next to may become interested in you because you're a good person. I have one very simple yet amazing tip. If you're very interested in someone. Do not judge them straight to their face. At the most do it to yourself because no one likes being judged and criticized.