I'm still in Bronze, so this advice isn't great, but think about what roles you play in normals, what are they? I don't care, play Rammus. OK? OK. Just kidding, but if you main jungle, definitely try
, his teamfight impact is greatly amplified by his ability to get from spawn to midway through the map with Homeguard
+ His Q. If you can land this ability on multiple enemies, and taunt an enemy Mage or Marksman, they will fall quickly. But besides that, pick champions that either aren't in meta ( Like Karma, Gangplank, Volibear, etc. ), or are old roles ( Zac top, Nidalee support/top, and others ). This isn't as risky as it sounds, and doing it will make greater impact, due to the fact people don't know your counter points. Side note, just because Katarina is left up, don't EVER blind pick her. If you don't know who you're against, you will be destroyed. Fizz, Xerath, Yasuo, Veigar, Vel'Koz, Diana, and any champions with AoE damage skillshots and multi-target CC will destroy you due to the fact your main damage source roots you, making you susceptible to getting hit with burst or getting ganked from the Fog of War. Rammus is a good blind pick, Kat is a terrible blind pick. That's the specific advice I can give you. Look at the middle section for more general advice. Good luck!