Challenger is currently a very popular comp that is fairly easy to play. You want to take either Draven, Master Yi or Ezreal as your Legend and focus on taking combat Augments. Play a high tempo game that is focused on win streaking most of your early / mid game to maintain a high HP buffer.
In early game you want to open with 3 Ionia 2 Challenger and add 4 Challenger in Stage 3-2. Push for Level 7 in Stage 3-5 or 4-1 and roll for Fiora/Kai'Sa and transfer items to them. Add 3 Demacia so Fiora will receive a powerful radiant Item.
It is usually easy to Top 4 with Challenger, but very hard to make Top 2 since you will eventually get outscaled. Your late game win condition often lies in Aatrox/Heimerdinger with Challenger Emblem or a 3 Star Tier 4 unit.