How to choose the most effective platform?

Firstly, determine your demographics, you'll want to choose one or two social media platforms on to focus all your marketing efforts on.
By investing the extra time on just a few channels, you’ll get better and quicker results, than if you were to try and invest in all the various social media platforms.
You will need to find a platform where your audience hangs out. Start narrowing down your choices based on the age of your audience.
Vine and Tumblr tend to be better options for a younger demographic, while LinkedIn and Facebook are better for an older demographic.
Whilst Facebook is starting to lose popularity among younger users, 70 percent of adults are still active on the site.