There are so many factors that could be influencing this situation. We can start with things personally controlled by you. Things that can negatively impact your performance include: playing while distracted(this game requires a considerable amount of concentration for all ranks, the more good habits you form though, the more you can concentrate on map, outplays, strategy etc.) Examples of things you can make habits are more consistent warding and locations, cs patterns, champion mechanics, ping/communication. Other things you can control that aren't necessarily habits are game understanding such as laning phase, lane priority and what to do when you have it, macro-play and working with team to prioritize the most optimal or advantageous objective, and back timing. Recalling at the wrong time is extremely common and can impact a game more than you'd imagine.
Tilt and mind-state is something, while taking quite a bit of effort sometimes, is a controllable factor that can lead to bad or risky decisions in game.
Those are a few of the things that you can control that can affect your progress.
Moving on, unfortunately, there are also many things difficult or impossible to control that will also affect your progress. These things can include:
**Match-Making: **Despite what riot claims, matchmaking can be very imbalanced and quite frequently in terms of bronze and silver. There will be games that are unwinnable from the very start regardless of rank. These are not common. However, in the lower tiers due to neglect on Riot's part there will also be games that start winnable and quickly become unwinnable due to players that join and don't understand the game even on a basic level, toxicity, players that have it in their mind that this isn't a team game and they don't have to even try to work with others, MMR manipulation (Boosting, purposely sinking MMR to match a friend, account sharing, etc.) Riot typically only bans players for toxic behavior and ignores any kind of inting, refusing teamwork, boosting, etc.
In terms of match making you will encounter toxic players (rightfully and wrongfully banned) on a higher account) that will attempt to climb on a new account, or a player just bored with their hardstuck main account at their true MMR so they play on an account at a lower one. I refer to both scenarios as smurfing though others may not agree.
Imbalanced Champions: This is another main topic where you have limited control. You get one ban, and there's a multitude of champions that are "balanced", yet constantly have their strengths specifically catered to with items, while others find it hard to even find runes or items that can synergize at all. This is why there is a lot of pressure in ranked to play specific champions, and styles according to the "Meta".
Bugs(minor component): Bugs ranging from champion abilities to client function to graphics etc. can lead to losses and forced dodges impacting your league points and match making rating, though this is rather rare.
These few topics should at least help you identify some obstacles to work over. Obviously focus on what you can control and try not to worry about what you can't. #Side note: If you previously played with abundant free-time but now don't have as much time to play, your performance can decay. Players with less available time tend to perform at a lower level as with any game.#
