Q:

How to install my own python module (package) via conda and watch its changes

I have a file mysql.py, which I use in almost all of my projects. Since I do not want to copy and paste the same file into each of these projects I wrote a module - possibly a package in the future. 
Question
How do I add a local module to my conda environment, and automatically update or watch it when I change something in mysql.py? How to do the same for a package?
I would like to avoid to set up a local channel/repository and just reference to the folder with mysql.py.

A:

While the previous answers are doing what I need, I just want to show what I will be using instead. Since it was my plan to learn about conda packages anyway... 
0. Good sources

Michael Sarahan - Making packages and packaging "just work" | YouTube
GitHub - audreyr/cookiecutter: A command-line utility that creates projects from cookiecutters (project templates)
and use one of these templates:

GitHub - audreyr/cookiecutter-pypackage: Cookiecutter template for a Python package.
GitHub - conda/cookiecutter-conda-python: A cookiecutter template for conda packages using Python (This is what I used)

1. Create a python package template for conda using cookiecutter
conda install -c conda-forge cookiecutter

Now change to the directory where you want to initialize your package, then do:
cookiecutter https://github.com/conda/cookiecutter-conda-python.git

This will ask for some basic information about the package that you want to create. Then change into your repo
cd myrepo

2. Build your package
make sure conda-build is installed, if not run
conda install conda-build

Make sure to set the CONDA_BLD_PATH as mentioned in anaconda - using a different conda-build root directory - Stack Overflow. This will be the directory where you can find your packages, then run:
conda build conda.recipe

to build your package and clean up after you with
conda build purge

3. Set up your own local channel (no uploading to anaconda.org)
Read 

Creating custom channels — Conda documentation 
python - add local channel to .condarc on windows - Stack Overflow

for help.
Index each platform. Maybe someone can confirm that this step is not needed, as my builds already  contain the repodata.json. Otherwise:
conda index D:\CODE\condamychannel\win-64

Test if the package can be found with
conda search -c file:///D:\CODE\condamychannel --override-channels mypackage

or add the channel to the config directly (per environment)
conda config --add channels file:///D:\CODE\condamychannel

4. Install (and update) the package
activate myenv

and
conda install mypackage

Once I change mypackage, I give it a new version number in meta.yaml and setup.py and build the package with conda build conda.recipe.
Updating is simply
conda update mypackage

See if your package works:
python
>>> import cli from mypackage
>>> cli.cli()
CLI template

This may not be the optimal way, but I could not find a tutorial that contains all the steps I outlined above.

A:

If you install the conda build package (and you have a package, not just a script), you can install in "editable" mode:
conda develop .

(running from the directory with your script). This is very similar to the "editable" mode from pip
pip install -e .

Either approach lets you uninstall packages with either
conda develop -u .

or
pip uninstall .

If you just have a script (not a package), you can edit or set the PYTHONPATH environment variable to include the directory with the script.

