Tip #3As you install new modules (say, with pip install) to support your Python application, add them to a requirements.txt file and do the same for your tests, as test_requirements.txt. Installation is then a simple:
pip install -r requirements.txt
What it does: It allows you to keep track of what packages are needed if you share your code, deploy it to other machines, or if you somehow have to rebuild your computer. You can also quickly test that the list is up to date by creating a virtualenv --no-site-packages, and then using a pip for that virtual environment to do the install.