League of Legends (LoL) Question: When should I start playing ranked?

Start rank plays when you are good at normal games. Good like, stays 2/0, farms better than everyone in the match, knows what/when to build certain item.
At least : Know how to play in every role with at least 2 champions. Have situational runes/masteries.
Select a main role, where you play better at.
I hope I helped.

Personally I waited a while after I hit 30 to get comfortable with the game and have a few champions that I enjoy playing and know inside out.

If you are at this point, then I'd say this is a really good time to start ranked, as it's nearing the end of the season, there is little to lose and you won't be digging yourself into a hole of low elo that you will struggle to get out of, as it will ( I believe) all be reset. As long as you don't have any expectations of getting to gold or higher (If you're new), then I'd say go for it, you have nothing to lose and ranked can be more accurate representation of how the game is supposed to be played, instead of a lot of 'experiments' in normals and people not really caring.

For this topic, please please don't just go on here and ask this question. Look at the higher elo accounts that are on this website, and message them. There are many different skills, gameplays, routes, techniques, and team play that revolve around ranked. Please don't go into a toxic, inexperienced player. If you want, message me on here and I will go indepth for you. When to go into ranked and other techniques to use once you go into ranked. Lane stalling, pushing, rotating, ganking, picking the right kind of team, so maybe you can pick a Crowd control jungler instead of going a full damage one when your team has no tanks. Just for example. But please please message me on here, and we can talk

What's really important is that you have 2 roles that you can play; with dynamic queue you choose a primary and secondary role before the game, and you need to be able to play both of them, not just your primary, so that in case you get your secondary role you can still do decently.

For every role you should train yourself to have good reactions, map awareness, when and where to ward and you should have at least 1 or 2 champions you do well on.

For ADC/mid/top you need to know how to last-hit well, control minion waves, how and when to trade etc etc

For support where to ward of course, how to properly trade, how to play vs specific ADCs/supports and how to support specific ADCs, how to deal with ganks and how to set up ganks for your jungler, etc

For jungle, when to take objectives, where the enemy jungle might be at all times, which lanes to gank and when, learn to smite Baron/Dragon so they aren't stolen, etc etc

If any of these things sound unfamiliar, you should learn about them now before playing ranked. MOBAFire is a good resource to learn, you can post a thread with any questions you might have or you could read up on guides, and aside from that reddit is good, you could check out the League subreddit or r/summonerschool to learn more. And ofc you can also just play a ton of games.

I jumped into Rankeds as soon as I hit 30, but I am a competitive person by nature. You should start playing ranked when you feel confident enough in your ability with 2-3 champions.

I would say start at the beginning of the next season. Reason being if you just hit 30 your still not fully ready to just jump into ranked and think you'll make it to high elo. take your time during the end of this season and get to learn a lot of the champs so that you can learn what fits your play style. Find out how to ward where to ward when to gank if you play jung your good and bad tendencies work on csing (probably the most important thing) just take time to learn the game. Just take my advice as a person that rush into ranked at the wrong time learn everything in norms and via videos and streams rather than jumping strait in and losing left and right until you realize you didn't understand thing like you thought you did.