apt-get install -y qgis cmake-curses-gui build-essential \
     git gitg meld \
     qtcreator qt4-designer 
     flex bison libgeos-dev libgdal1-dev \
     pyqt4-dev-tools libgsl0-dev libexpat1-dev libproj-dev \
     libqwt-dev libspatialindex-dev libqscintilla2-dev\
     libqscintilla2-dev python-qscintilla2 python-dev python-sip-dev \
     python-qt4-dev postgresql-client-9.3 \
     libfcgi-dev

Open QtCreator.

Now do File -> Open File or Project

Select the CMakeLists.txt file in the top level of your QGIS source tree.

Change the Default build path from:

/home/timlinux/dev/cpp/build-QGIS-Desktop-Default

to

/home/timlinux/dev/cpp/QGIS/build

Make the build directory if needed using the Browse... button. Also replace /home/timlinux/dev with appropriate base path the username etc.

Click on configure project

It should complete with the sentence in the General Messages view:

"-- Build files have been written to: /home/timlinux/dev/cpp/QGIS/build"

Now tweak the CMake configuration:

Click on projects on the left hand side icons.

On the Build & Run tab enter the following into CMake arguments:

-DQWT_INCLUDE_DIR=/usr/include/qwt -DCMAKE_BUILD_TYPE=Debug -DCMAKE_INSTALL_PREFIX=/usr/local/qgis-master -DPYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython2.7.so -DQSCINTILLA_INCLUDE_DIR=/usr/include/qt4 -DQWT_LIBRARY=/usr/lib/libqwt.so -DWITH_MAP_SERVER=OFF -DWITH_SERVER_PLUGINS=OFF

Now click the build hammer icon on the left icons

Note the above arguments assume you are using Ubuntu 14.04 64

Tweaking your build:

In projects, build & run, under Build steps -> Make click Details and enter:

-j8 in the additional arguments box

(replace 8 with the number of cores you can build with)

Click the hammer again and you should get a much faster build.

Running QGIS