Im really bad at picking champions, and i want to choose someone that i can practice a lot with to carry in ranked, my favorite role is top, and my best champions in top are nasus, gangplank, darius, and sion. If anyone has any suggestions to someone you think id like to play, they would be greatly appreciated!
Might want to try gnar. He's really fun and mega gnar entire kit is cc while mini is practically uncatchable. Might feel like a combination of gp and sion.
I really enjoy playing Illoai. Her E is one of the most fun skills in the game. She is a lane bully and can carry if you can get ahead.
Hey I typed my main champs into here and it found me champs that those players typically also play http://na.leagueoflegends.com/en/page/find-your-lunch-table-which-champs-are-friends Anyway, I used to main nasus with over 111k so I can tell you who I enjoy now in top. I enjoy gangplank as well so maybe this will work for you.
If you want to stick to top, irelia is a fun choice. It's easy to farm like nasus with the q but it resets on kill and refunds some mana so farming every creep is a breeze once you get used to it. It's also good for gapclosing because it's a jump. It applies on hit effects like sheen which nasus q also does but it's a gap closer. You have the W which gives passive sustain like nasus has and a bit more true damage and healing when you activate it. The E is good to slow the enemy down but if you start to lose you can stun them, so it's like a nasus wither on steroids that lets you stick if they're running, disengage if it looks bad, or just get the upper hand. The ult gives you a bit of healing in the fight to sustain like nasus but also you can use it to clear a wave fast because of the minuscule cooldown. Also helps catch running champions with a nice snipe skillshot.
If you are willing to try jungle, udyr is a blast too. He is very fast and hard to run away from, has high sustain, and you are good for split pushing. I won't go into details unless you ask because you main top, but he's really fun.
I'm thinking 
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