Readme tweaks

README.md

@@ -36,7 +36,7 @@ Usage
 
 ### Minimal setup
 
-- Create a `.travis.yml` file in your repo.
+- To build Linux and Mac wheels on Travis CI, create a `.travis.yml` file in your repo.
 
     ```
     language: python
@@ -58,7 +58,7 @@ Usage
 
   Then setup a deployment method by following the [Travis CI deployment docs](https://docs.travis-ci.com/user/deployment/), or see [Delivering to PyPI](#delivering-to-pypi) below.
 
-- Create a `.circleci/config.yml` file in your repo,
+- To build Linux and Mac wheels on CircleCI, create a `.circleci/config.yml` file in your repo,
 
   ```
   version: 2
@@ -71,13 +71,11 @@ Usage
       steps:
         - checkout
         - setup_remote_docker
-
         - run:
             name: Build the Linux wheels.
             command: |
               pip install --user cibuildwheel
               cibuildwheel --output-dir wheelhouse
-
         - store_artifacts:
             path: wheelhouse/
 
@@ -87,13 +85,11 @@ Usage
         xcode: "10.0.0"
       steps:
         - checkout
-
         - run:
             name: Build the OS X wheels.
             command: |
               pip install --user cibuildwheel
               cibuildwheel --output-dir wheelhouse
-
         - store_artifacts:
             path: wheelhouse/
 
@@ -105,9 +101,11 @@ Usage
         - osx-wheels
   ```
 
+  Note: CircleCI doesn't enable free macOS containers for open source by default, but you can ask for access. See [here](https://circleci.com/docs/2.0/oss/#overview) for more information.
+
   CircleCI will store the built wheels for you - you can access them from the project console.
 
-- Create an `appveyor.yml` file in your repo.
+- To build Windows wheels on Appveyor, create an `appveyor.yml` file in your repo.
 
     ```
     build_script: