What is the best way to post your blog content to Facebook and Twitter

By far, the best method is to create your Facebook and Twitter posts manually, somewhat based on what you are adding to your blog. This provides the greatest amount of creativity and originality, both of which are rewarded more than autoposting in social media marketing.
If you know you will not find time to post to your Facebook page and Twitter, then probably Jetpack has the best method for autoposting to Facebook and Twitter. I say this because Jetpack is well coded and constantly updated. This is a big for connecting your WordPress website to a 3rd party like Facebook since there are so many ways for these kinds of connections to break when the 3rd party changes something.
Zapier and If-Then-Then-That (IFTT) provide good services to connect your blog to Twitter and Facebook. I prefer Zapier.