MIUI tricks

1. Using the phone dial pad, dial *#*#6484#*#* and you will get a “diagnostics screen”, from which you can check out system information, as well as perform various tests on the phone. As a mnemonic: 6484 is “MIUI” in the dial pad.
2. In the recent apps screen, hold down the clear button, it will launch the installed applications list from where you can uninstall applications and also set and remove default applications. I used this myself to access the default launcher and browser settings when I was experimenting.

Get Google Apps "gapps" or Google Play Services on MIUI 6 (Xiaomi)

Two days ago, I updated to MIUI 6 from a ROM I downloaded from this thread in the MIUI forum : [ROM] [Mi3W/C/4] [Google] [MIUI 6] v6.2.1..0 KXDCNBK. I just installed it via the Updater app and afterwards everything was working fine. Afterwards, Google Play, synchronisation of Contacts stopped suddenly. I was sure they were working correctly after the installation. Bizarre.

How to get back Google apps, or install Google Play Services:

Got the above link from MIUI forum post (How to Install Google Play/Google Apps on Xiaomi Phones?)There a link to a Chinese language (?) application called Google Installer, where you can choose which Google Application (Play Services, Games, Contacts sync, Calendar sync etc.) that you want to install:

Download (APK) : Google Installer to Install Google Play Services

Also see:

1.  Google Play Services (Wikipedia)
2. How to install and solve Google Play errors (MIUI Forum post)