Install the OS from an image file
If you don't want to use the NOOBS install (its slower to install and adds a delay on powerup with its restore prompt screen) see the Win32 Disk Imager instructions here.
When running for the first time use the automatically run config tool option to expand the file system to fill the SD card you are using.
Install the OS from The NOOBS Package
Format The SD Card
Download the SD Card Association’s formatting tool from here and install.
Run the installed "SDFormatter" application.
Set "FORMAT SIZE ADJUSTMENT" option to "ON" in the "Options" menu
Check that the SD card you inserted matches the one selected by the Tool and click the “Format” button.
Copy On The RPi NOOBS Software
Download the NOOBS (New Out Of Box Software) package from here.
Unzip the downloaded file and simply copy the extracted files onto the SD card you formatted.
Initial Tasks
Default User
Username: pi
Password: raspberry
GUI Raspberry Pi Configuration
By default newer version or Raspbian boot straight into the GUI. Menu > Preferences > Raspberry Pi Configuration
System tab
Change the 'Boot' option to CLI (command line interface) if preferred
Turn off Auto Login if not desired
Interfaces tab
Enable any interfaces that are needed.
Performance tag
Reduce the GPU memory to 16 if you do not plan to use the GUI interface and want to maximize the memory abailable to the CPU.
Update All Packages
sudo apt-get update
sudo apt-get upgrade
Resizing the disk to fill available space
Raspbian has a tool to do this, BUT beware, it will fill the entire SD card. If you plan to make an image of your card to copy onto other cards in the future you don't want this because cards are not all exactly the same size! Two 8GB SD cards do not necessarily have the exact same available memory on them so you need to leave some headroom, or when you try and use your created image on a card that's slightly smaller you won't be able to. Instead use gparted and fill the card leaving a chunk of space at the end unused – see our guide here.
Setting A Custom Password
At the command line type:
passwd
Connecting Via SSH
If you want to connect via SSH, so you can copy and paste commands etc, get the IP address of the eth0 adaptor:
ip addr
Then use your favourite SSH tool to connect (e.g. FireSSH for Firefox)