I honestly appreciate the work and effort that people put into making guides as I think many people find them useful. But I never saw really saw relatively broad advice as being helpful. I won a lot more by playing different champs/ roles each game. If I think a game is over I'll afk or spam...
I think the only way you can get banned is by advertising that you are boosting. I've logged onto several account in a single day without using a vpn and all of them have been fine. Always remember to stay in touch with the person you're boosting and give them updates, ask if you really need to...