When you approach d1, and then master, and then low challenger, and then about 600lp+ challenger, you find there are differences in skill level. Mechanics are generally the same, although you will always be inferior to one-trick pony/game spammer on a particular champion. The key distinguishing factor is simply game knowledge.
Subsequently, you'll find that a lot of high elo players can get away with playing whatever they want since games often turn on game knowledge; you can first time champs in high elo and still not be too punished if you have the requisite game knowledge and baseline mechanics.
If you want to climb, you have to work on that game knowledge. That can come through just spamming games in D1 and over time you'll just acclimate to that skill-level game knowledge wise. Alternatively it will be in just knowing where to be on the map, knowing how to manipulate waves in certain situations, respecting the enemy jungler, respecting objective timers, and playing to the teams strengths.
So for example specifically, sometimes you can tell when a fight is about to break-out; you're bot lane is pushed and aaing the turret, they're going to get ganked (note the enemy jungler will probably know this and also be there). A lot of junglers don't respect the enemy junglers, and force an unfavourable 3v3.
Wave manipulation is really just knowledge; you should know it if you're a laner in d1, otherwise go lookup a youtube video. Time your wave manipulation so a large wave crashes on the tower at around the baron spawn time; as a top laner, if you have TP and your team has baron pressure, you get a free objective; if you're a turret taking champ, you can just tp to the turret with a huge wave, and have your team start baron.
Knowing when dragon is, is also important, setting up vision (Scuttle crab), getting a successful gank off immediately before dragon, so as to snowball that into a dragon and a free back.
Knowing your teams strengths, win-conditions, and spikes. If you watch pro game-play you'll hear casters talk about this a bit. For example, some comps want to siege mid-game, see Caitlyn, or Tri-Force Corki. Some comps are poke-heavy and want to avoid team fights, such as Varus Mid, Corki ADC, Nid JG (as an example). Other comps want to rape you, such as Malphite, Alistar, Diana, etc. Other's want to scale, other's want early game; play accordingly. If there's a JG eve, she needs to snowball, and you play to her win condition by greedily going in for that cs and dying.
All these things you should know, but perhaps putting them here for you to read might give you an idea of the things you ought to take into account; I haven't even talked about how to team fight as well, or setting up picks, or warding/denying vision, roaming, etc.
