Consistency Is Key
Players often confuse beginner friendly champions with beginner only champions. Honestly speaking, these same champions don't drop off drastically in win rate as you get higher in divisions. In fact, one-tricking these champions may often be the key to climbing ranks.
Some players think this becomes too boring, but if you're series about improving your game intelligence without needing to worry about your in-game mechanics, this is the way to go.
Garen
The king of easy champions, Garen is nearly foolproof. No skill shots to miss and early game domination. He's also very difficult to kill or cheese, meaning that there are few instances where Garen will be a gold granting burden to his team. While some players may complain about his lack of utility, they'll certainly complain more about a 0-10 Yasuo top.
Nasus
An upgrade from Garen in terms of skill complexity, Nasus is still very consistent. As a Nasus player, you'll focus in on map pressure, farming, and closing out the game while you're ahead. Similar to Garen, Nasus has a ton of built-in sustain that allows him to power his way through bad match-ups. Worst comes to worst, he also has a ranged spell that deals a decent amount of initial damage, allowing you to last hit from afar.
Malphite
This guy's a perfect pick to go up against the multitude of AD based top laners out there. He's a bit mana starved, but doesn't need much in the way of CS to be effective. If you want to participate in team fights but aren't particularly fond of conflict top lane, Malphite is an optimal pick to maximize some high consistency, high impact plays.
Volibear
Volibear provides some diversity from all the tanky bruiser top lanes to some tanky bruiser junglers. He's still very much a front line champion, but alllows players to make map rotation plays rather than focusing on last hitting and harass. He's still relatively unplayed, which allows you to capitalize on players who are unfamiliar with how much damage he can dish out.
Rammus
Rammus is the Malphite of the jungle and AD based champions tremble at his name. His ganks are even easier than Volibear's as a result of his higher movement speed, but sacrifices burst damage for survivability. While he's not as effective against a magic damage heavy composition, his crowd-control and gank power is still very good for any team.
Malzahar
Despite having a skillshot, Malzahar is still a champion that I would say is one of the most consistent out there for mid laners. His laning phase is highly anti-social, and by auto-clearing waves with his E, he's able to avoid skirmishing too often with the enemy laner.
Singed
Back in the top lane, Singed tends to be a champion that players like to one-trick as a result of his simple yet effective strategy. There's some variety in the strategy to use, but otherwise Singed players simply need to learn which match-ups they can win and what spells to watch out for. Otherwise, they can focus purely on dodging skillshots and map rotations while running around inflicting poison on everything on the map.
Teemo
Similar to Singed, Teemo is largely a matter of learning which match-ups are favorable and which ones will get you killed. After that, it's simply a matter of abusing your range and blind on every champion available. This is generally more than enough to win you a game no matter what your teammates perceive, and it's apparent by his consistently high win rate amongst one-tricks.
Nautilus
The problem with most supports is that while they may be consistent, they're also prone to being cheesed and feeding their faces off as a result of their low health. Nautilus is not such a champion, and his ultimate is perfectly undodgeable. Point and click ranged CC really is the best.
Caitlyn
Finally, I have mixed feelings about Caitlyn, but she's certainly one of the most consistent marksmen out there. Once you learn her range, the rest of the game is simply about auto-attacking for the most part and dropping a trap here and there. Although she's harder than she looks, players that enjoy her really do become very consistent in almost every meta.
