How can I install commonly used developer tools?

build-essential is the main one that springs to mind.

sudo apt-get install build-essential

The Ubuntu SDK is the recommended way to develop apps for Ubuntu.

The Get Started page on the Ubuntu App Developer site will always contain up-to-date information on how to install the SDK and all related tools. In any case, here's how:

For Ubuntu 12.10 and Ubuntu 12.04 LTS users:

sudo add-apt-repository ppa:canonical-qt5-edgers/qt5-proper && sudo add-apt-repository ppa:ubuntu-sdk-team/ppa && sudo apt-get update && sudo apt-get install ubuntu-sdk notepad-qml

Alternatively, for those using Ubuntu 13.04 or a development release:

sudo add-apt-repository ppa:canonical-qt5-edgers/qt5-proper && sudo add-apt-repository ppa:ubuntu-sdk-team/ppa && sudo apt-get update && sudo apt-get install ubuntu-sdk