Problems setting up Python development server at http://127.0.0.1:8000/
You do not have to do more than you have done, however, you should make sure that you do not have the server from your previous project running, for one.
To confirm, are you at the point in the tutorial where you have run django-admin.py startproject mysite . You have also run python manage.py migrate.
Also, make sure that you are running python manage.py runserver such that the manage.py you are running corresponds to the manage.py in your new tutorial project. That is, check which directory you are running from.
I'm running into problems trying to use "python manage.py runserver." 
According to the tutorial, I'm supposed to get a  “Welcome to Django” screen when I visit my development server at http://127.0.0.1:8000/ but instead, I see one of my previous projects that's locally hosted on my computer. I'm wondering why this is, do I have to more specific or specify another when I use "python manage.py runserver"