As of Tensorflow version 1.0 installation has become much easier to perform. At minimum to install TensorFlow one needs pip installed on their machine with a python version of at least 2.7 or 3.3+.
pip install --upgrade tensorflow # for Python 2.7
pip3 install --upgrade tensorflow # for Python 3.n
For tensorflow on a GPU machine (as of 1.0 requires CUDA 8.0 and cudnn 5.1, AMD GPU not supported)
pip install --upgrade tensorflow-gpu # for Python 2.7 and GPU
pip3 install --upgrade tensorflow-gpu # for Python 3.n and GPU
To test if it worked open up the correct version of python 2 or 3 and run
import tensorflow
If that succeeded without error then you have tensorflow installed on your machine.
*Be aware this references the master branch one can change this on the link above to reference the current stable release.)