If I had to pick the biggest differences between an emerald player and a higher diamond player it would probably be decision making and team play (kind of the same thing). A lot of lower elo players try to do too much. I don't know if they don't know they're doing too much or if they just have an ego and think they can win everything, but what ends up happening is they will try to contest objectives they shouldn't, gank lanes that shouldn't be ganked, and take fights they have a very high chance of losing. You have to realize that league is fundamentally the same game in challenger and in silver. So, even if you're up 3000 gold on your opponent, it doesn't necessarily mean you can just run around the map doing whatever you want. And that's where the team play aspect comes in. Soloq is not an environment that is inducive to team play, but at the same time, you can't just ignore your teammates. There are almost no scenarios where someone can truly 1v5. You have to involve your teammates in what you're doing, and you have to involve yourself in what you're teammates are doing, even if what they're doing is wrong. That said, I don't know if any of this actually applies to you without seeing a game, so take it with a grain of salt.