I think sharing on social media platforms unless you have a strong target audience following is highly ineffective and timewasting (this is honestly been my experience). Because a lot of the time, my watch time is hurt by doing this...So be careful with this one

I've tried answering questions on other platforms like Quora, my answers get views & upvotes but I don't think people actually click to the YouTube platform so my views don't get increased.

I think for me what has worked so far is - commenting, improving thumbnails & reworking titles. And sharing my content on social media platforms sparingly..

ALSO what has worked is actually making longer videos and trying to make them more engaging with b roll and graphics (time-consuming) to increase audience retention BUT my clickthrough rate is still awful (0.4% to 6%). I honestly think long term promoting on socials is highly ineffective UNLESS you're also building your other social networks together and allowing them to tag team each other as time goes on...