This is my own python3 + flask starter-kit, it will be improved with time. The goal is to keep it simple and have something to get started.
I suggest using virtualenv, and more specifically virtualenvwrapper.
Once you have the command line installed, create your virtualenv:
mkvirtualenv my-super-app --python=/usr/local/bin/python3 (your python binary might be elsewhere).
Then when you come back to the project later, you do:
workon my-super-app
Install the dependencies:
pip install -r requirements.txt
Start the server:
python runserver.py