Firstly, download this zip file and extract it. After the zip extracted, you will see google play services collection fro MIUI V6 folder. First,Google account manager.apk , google service frame.apk ,google play services and google play install to your phone step by step. Other, Apps are as you like. Now, your phone can access the google play services. If you facing with google services error, you must uninstall all of the google applications. And install it again from the start.

Download: Google Service For MIUI V6