People say this a lot but listen (analyse) to the different mediums where sound design is used. I'm no expert but when I'm listening I ask myself why that sound is used as pretty much everything you hear was a conscious choice, I always try to keep that in mind. Also many sounds sound alike, think about what you think it sounds like and how you would create it not only to kind of deconstruct the elements used to create it but you can also get behind the emotion it's trying to convey to tell the story which is the main goal of sound design. Find the overused/cliche tricks used and take advantage of them but in a way that it seems new and not forced, take camera angles for example they say when you look at a character from a low high angle their supposed to be weaker and smaller but when seen in a high low angle they are more dominant and stronger than the other, what would be the sonic equivalent to that? How can you make a listener distinguish the difference between a good guy and bad guy?.
A lot of thought is put into a good "designed" soundtrack, when I was starting out like most people I thought it's just about creating cool sounds and plugins used to process them until I did my research. Hope this is helpful, good luck.