Strategies, odd calculations, as everyone mentioned, take some time reading books, articles and watching videos, you could also watch a couple streamers on twitch. Most important of all though is experience. If you ever venture to the live side of the game I would also note, body language is very important, when you play live the game becomes a completely different beast. At that point you want to be playing the person every which way possible, imagine who they are, what they went through on that particular day possibly. If you've never been good at reading people, I believe live poker also considerably increases that skill. Surprisingly the game really does bring out the worst in some people, and it astonishes me how some react at the table. It is a game after all and it's supposed to be fun.