Try putting yourself in your opponents shoes, and learn to put them on a hand. Ask questions like “Why did he re-raise me that amount?”, and “Why did he only call in the previous betting round?”, “Maybe because he only called me, he has a kicker problem?”
That's the psychologocail part of poker. Tryin to read the other player's mind by his betting patterns, his facial expressions, his hand tells. You have to think like your opponent if you are going to truly beat them.