How to reduce lag in Minecraft when playing through a VPN?

I sometimes play this game while at work and since online games are blocked here, I usually play through a VPN. There isn't any particular policy regarding playing via a VPN so that is not an issue. The problem is the lag that occurs when I connect through a free VPN service. Any tips on how to fix this would be appreciated.

Read more: How to reduce lag in Minecraft when playing through a VPN?