Gold to plat was not very different. The occurences of someone that's really good increases dramatically however, and people are somewhat more mechanically skilled. Plat 5 should still be considered gold because theres honestly very little difference between the two. If you're just gold 5 right now, concentrate on climbing to Gold 1 first learning what you should be during the process. Plat V-Plat III can still be considered relatively the same, since people still don't understand how to make decisions based on their situation. Around Plat 2-Plat 1 the game gets a lot harder, and mechanics and game knowledge increase drastically. If you ever get that high, you will quickly notice the atmosphere of games change, and it demands more and more to keep up at that rank.
To get plat isn't hard in itself, but if you're struggling at low gold, it would be harder to get to high gold first.
Focus on game knowledge and decision making. Its the number one thing that loses games in plat and gold. People have mechanics and understand most about their champions, but decision making is terrible.
Things like, knowing where the enemies are and what is their next move. Understanding wave management and how to apply pressure with that. Know your limits and when and when you can't win a fight. Learn to make sacrifices and most importantly learn how to teamfight. Gold teamfights are all over the place with positioning and diving. Communicate with your team and make a solid game plan to win the game, and you'll climb quicker than those that are greedy and act impulsively.