Games are either extended 20+ mins or losses because people ignore me. A call was only listened to after me and another teammate kept reiterating it over and over until they said "fine" we went from inner towers to all 3 inhibs down in 2 minutes.
A few tips:
Start small and work your way up so that people get used to you (correctly) calling things. As support I usually work my way up from 'hey, I can 1 shot if I land e, so Tag them if I do' to 'I've got wards for drag, we let's go take after we kill them' and that sets people up for big calls like 'shove out top as 5, then let's rush baron' instead of just jumping to the last step.
Give an end goal. Don't just say 'hey, let's 5 man bot' cause then it feels kinda open ended, and someone will leave to farm a side wave. You're better off with 'they can't stop our siege, let's force that bottom turret then reset before drag'
Make people think it's their idea. People always like thinking they're smart, wording your calls to give your team an option of 2 good calls makes them feel like they are shot calling correctly, which makes things run smoother. 'hey, yall wanna 5 man bot or top while we have supers mid?' and the like.
Lie with pings. If you use normal pings by an objective it doesn't show whose pinging. So use a few of those, then followup in chat with 'ah yea, I have a pink for that baron, we can do it' or 'oh yea, we could definitely rush that'
It pretty much comes off as how to communicate and get people to trust what you're saying without insulting them or forcing them around.
