In Contacts press Menu - More - Display options - Display contacts by.
Then select either First name first or Surname first.
It is best to avoid task killers such as Advanced Task Killer. Android is designed to automatically pre-load certain applications, even if you don't load them yourself. If it starts to run low on memory, it will smartly unload the oldest running apps automatically.
Manually killing tasks will only mean they get loaded in memory again. Task killers can make the tablet slow, laggy, or drain battery life more quickly.
If you are running low on tablet memory, you can look for your largest applications to uninstall. Go to Settings - Applications - Manage Applications and press Menu. This will then filter your apps by memory use
If you want to browse websites, but not leave sign of cookies, search history or cached items, then you can use Incognito mode. Open the Browser and press the + (Action Bar) icon in the top-right. Then press New Incognito Tab.
There are a number of ways, as below. The first two of these may be disabled on some networks/carriers or Android versions however.
1) Go to Settings - Applications - Manage Applications. Then chose All at the top. Then scroll down to Contacts Storage - Clear Data.
2) Go to Contacts. Then press Menu - Delete. Then press Select all (at the top) and then Delete again.
3) Go to Settings - Accounts and sync. Then untick Background data and Auto-sync. Then go to Gmail (or an account that your tablet syncs with) and delete all of your Contacts from there. Then re-sync your tablet.
4) Download an App called 'Delete All Contacts' and use that as a last resort.
These methods above will delete contacts from the tablet only, not the SIM card.
If you're worried about your sensitive data falling into the wrong hands then Jelly Bean has a great new encryption feature that scrambles every pieces of content on your device.
Go to Settings - Security settings - Encryption to enable it.
With Android Jelly Bean you can now take photos while recording video by simply pressing the screen.
This will save that particular frame to the gallery while continuing to record video.
To quickly hide the on-screen keyboard, press the Back button
If you want to remove an entire text message thread, go into Messages and look for the thread. Then long press on it and select Delete thread
There is no need to be stuck with the standard Android keyboard.
Go to the Android Market and search for 'Keyboard' to see some great alternatives, many of which are more accurate and make typing much easier.
A good one is GoKeyboard.
If you see a warning saying the keyboard will collect all information (including credit cards) just ignore this. This is just a security feature that Android shows for every third-party keyboard that you install.