let's start from what Steem is,Steem is a crytopto coin which is either bought or mined and is tradeable with other crypto coins.
Steem and it's activities are done on a platform known as steemit.
promotion of Steem is not a personal duty rather a collective duty but could be driven by a personal idea ,I will be drawing instances from some Steemit communities.
taking a look at some tags and comunities it is as if Steem is meant for the technologically inclined personells but the people that can make use of Steem so much may not know much about technology the use of smart phone and computers.it is an undeniable fact that one of fastest way to pass information or to educate people is trough the church,
just like what # Steemchurch is doing by preaching the gospel and trough that earns,by reading the gospel and through discussion of it earns too who doesn't like that?
I am going to now list few ways which I can promote Steem if given the opportunity.

Adverts on radio and televisions.

this it the most common way of passing information and its user friendly to those not used to smartphone technology and engaging them trough
development of radio stations where you can earn trough active interaction with the organisers of the radio show, reporting of accidents or news or anything which helps save life or helpful the occupants of a certain communities.

Educational sector.

it is not arguable that other mean of educating a nation is trough educational sector. Steem promotion can be done by introducing to schools if Steem can be adopted in schools both high schools and universities as a mean of reward for academic performances for instance if an assignments is given to students and student are to do it and submit online through a Steemit block chain app or site and they get their reward in Steem and also in grades you will observe that students will be eager to do assignments their by promoting both the use if Steem and learning at the same time.

making a movie about it.

practical demonstration of the importance and ways of usage can go along way in promoting Steem and can be fun at he same time.

adverts on other social media like.

facebook,Instagram,twitter and testimonial videos on youtube will definitely have an pact in Steem promotion.