[Android General] bliind:
MIUI is not like other Android ROMs. It has a full UI overhaul and adds a bunch of extra customization. A lot of the really nice features that made Gingerbread MIUI nice have been incorporated into ICS, and even more incorporated into CM9/AOKP... but not all of them. This guide is going to gloss over the features that are now standard in ICS and focus mainly on MIUI specific features.

*These features are as of the most recent MIUI version, some may work in older versions, some may not*

Some things to start with, just some quick things that I do every first boot:

Enable root: Find the Permissions app, turn root switch to ON.

Turn off 3G download limit: Downloads app, menu > settings > turn off Data download prompt

Change battery display: Settings > Battery > Battery indicator style. My personal favorite is top-bar

Set long-press back button to kill app: Settings > Button > Long-press Back to kill app, and delay time underneath

Customize toggles: Settings > Status Bar: Choose full page/compact toggles, Customize position underneath.

There's some more cool features in those menus, I implore everyone to explore the settings app thoroughly.

MIUI Home

Where's the app drawer? Well, there isn't one. Installed applications are placed on your homescreen. There are some ways around this. One way is to put your apps in a folder and place that folder in your dock. Another way is to simply use another launcher such as Apex or Nova. Yet another way would be to use an app drawer app, such as AppDrawer.

Enough about what MIUI doesn't have, lets get into the cool aspects of the launcher:

The dock: You can have up to 6 icons in your dock, and as little as none, including folders. It auto-rearranges to fit your icons centered.

Two & Three finger pinch: Pinch the home screen with two fingers and you enter widget edit mode. Easily rearrange widgets and icons from page to page and customize MIUI widgets (more on that later). Pinch with three fingers and you enter the home page edit mode. Here you can add more screens, remove screens and rearrange them. One nice thing you can do when creating a new screen is to grab directly from the + logo to where you want that screen.

Multi-touch icon placement: Pick up an icon or widget with one finger, and you can slide pages with your other finger for easy page movement.

Widgets: MIUI has some really amazing looking widgets including 3 clocks, 3 picture frames, and a full size music widget. These widgets are made even more amazing by their ability to be themed. There's a bunch of widgets available for them through the theme manager. One really nice thing about these widgets is that they don't update when you're not on that homescreen. This saves battery life and RAM consumption.

Lockscreen

Custom MIUI lock screens can do almost anything. The stock lock screen can unlock normally, unlock to messaging, phone, or camera. You can double tap the lock icon to bring up music controls and a visualization, though this will be shown automatically if you have music playing. You can preview unread text messages and missed call callers by holding the lock icon.

Then there's two features that work regardless of what lockscreen you're using. You can hold the home button to turn on the flashlight if your phone has a flash, and you can hold the back button to unlock directly to camera (in recent builds this needs to be enabled in Settings > Button)

Theme Manager

Probably the best feature of MIUI is the Theme Manager.

You can apply themes like normal, or mix and match pieces of your themes together in the "Mix" section.

You can pick pieces of full themes to not apply picking the theme, then choosing the icon in the bottom left. Really like your icon pack? Uncheck "Icons" and hit apply, you get the rest of the theme, but keep whatever icons you had before.

You can save your mix & matched themes. From the Mix section, hit menu > Backup Theme

Themes go in /sdcard/MIUI/theme or you can select them from the File Explorer, or open Theme Manager and menu > Import from SD Card

Besides themes, the Theme Manager is also used to manage ringtones, notifications, and wallpapers.

Place ringtones and notification tones in /sdcard/MIUI/ringtone

Place wallpapers in /sdcard/MIUI/wallpaper

Permissions Manager

The Permissions Manager is split into three sections, root permissions, permissions, and auto-start

Upon installation of an apk off your sdcard, you get asked to grant individual permissions, set "I trust this app," or the default setting will ask you as the app asks for each permission.

The Autostart manager will stop apps from running when your phone boots.

Network Assistant

In the Network Assistant, you can set a maximum amount of traffic to be sent over 3G if you have a limited data plan. It will also tell you which apps are using the most data, and by pressing the button at the bottom of the Traffic Ranking screen, you can limit apps' internet usage. From there, you can also set the default settings of newly installed apps, useful if you want to set apps to only use data off wifi.

Visitor Mode & Access Control

These settings are hidden a little bit. To access them, go into Settings > Security & privacy > Privacy protection

Guarded mode is also known as visitor or guest mode. When visitor mode is on, call logs, notes, gallery data, and text messages are hidden and the launcher cannot enter edit mode. You can also set a password for leaving visitor mode.

Access control gives you the ability to password protect applications. The ability to hide the apps is currently missing but should show up in a later build.

Firewall (formerly Do Not Disturb)

Using the Firewall app, you can send unwanted callers directly to voicemail and reject text messages as well. It has a lot of customization including a whitelist or blacklist and keywords for blocking text messages.

App Killer

MIUI has a built in app killer. You can access it by holding the home icon. It looks similar to the stock ICS task switcher, but looks a little nicer. It functions the same way, you can slide apps away to remove them from memory. There's also a little brush icon in the bottom left for clearing all apps from memory. The little icon in the bottom right takes you to the Running Services settings menu for further control over your running apps.

Miscellaneous Features

A few scattered features between apps.

T9 Dialing: Using the keys on the dialer, you can spell out your contacts' name to find them. For instance, to find "John" you would dial 5646

Long press editing: In almost any MIUI app with a list, (dialer, messaging) you can long press an item to enter editing mode. Select as many items as you want and select one of the options that appears. These options vary from app to app, but all include a "delete" option.

Long press toggles: You can long-press any of the toggles to enter the settings menu for that toggle. For instance, if you long-press the wifi toggle, you go to wifi settings.

To be continued

I'll keep updating this as MIUI gets updated. Feel free to post some suggestions and features you think are cool.