usability - Is there a more effective way to convince users to sign up with their social media accounts?

The current design for a sign-up page of mine is split into 2 sections - Sign up using your social media account on the left and a sign-up form with 5 inputs on the right. We ran a quick user test and found that more people were signing up with their emails. We want to encourage users to connect with their Facebook/Twitter accounts instead.

I researched the matter and saw that some sites display the social media links prominently and have a smaller Sign up with email text link. Users need to click the link to access the form.

Those solution are only ones I have found so far. I am wondering if anyone has had these design requirements and found a more effective solution?

Update: I also found a solution where the site says something like "Don't be old-school. Sign up with Facebook instead". It sounded a bit rude, and I'm not partial to this solution.

Answer

We ran a quick user test and found that more people were signing up with their emails

If you trust your test, then you should trust your users and design a solution that meets their desires.

We are trying to encourage users to connect with their Facebook/Twitter accounts instead

Why is that? Do you have sound reasoning behind this in that it will ultimately provider a better experience for the user? If so, share that reasoning with the user. Be up front with them. "Consider using your social media account because X Y, Z..."

I also found another solution where the site says something like "Don't be old-school. Sign up with Facebook instead"

But that's not sound reasoning. That's just an annoying sales pitch. You have to explain to the user--succinctly--as to why it benefits them to use their social media account.

You also have to consider the reasons people may not want to use their social media account. I rarely want to use Facebook to log in to sites with--mainly because I never really know what that connection is and if this new site is going to start sharing things on Facebook without me being fully aware of it. So there's likely some legitimate concerns people have that you may have deal with as well.