update contributing.md

docs/CONTRIBUTING.md

@@ -1,46 +1,41 @@
 # How to contribute
 
-Our software is open source so you can solve your own problems without needing help from others. And if you solve a problem and are so kind, you can upstream it for the rest of the world to use.
+Our software is open source so you can solve your own problems without needing help from others. And if you solve a problem and are so kind, you can upstream it for the rest of the world to use. Check out our [post about externalization](https://blog.comma.ai/a-2020-theme-externalization/).
 
-Most open source development activity is coordinated through our [GitHub Discussions](https://github.com/commaai/openpilot/discussions) and [Discord](https://discord.comma.ai). A lot of documentation is available on our [blog](https://blog.comma.ai/).
+Most open source development activity is coordinated through our [GitHub Discussions](https://github.com/commaai/openpilot/discussions) and [Discord](https://discord.comma.ai). A lot of documentation is available at https://docs.comma.ai and on our [blog](https://blog.comma.ai/).
 
-## Getting Started
+### Getting Started
 
  * Setup your [development environment](../tools/)
  * Join our [Discord](https://discord.comma.ai)
  * Make sure you have a [GitHub account](https://github.com/signup/free)
  * Fork [our repositories](https://github.com/commaai) on GitHub
 
-## Testing
-
-### Automated Testing
-
-All PRs and commits are automatically checked by GitHub Actions. Check out `.github/workflows/` for what GitHub Actions runs. Any new tests should be added to GitHub Actions.
+## Pull Requests
 
-### Code Style and Linting
+Pull requests should be against the master branch. Welcomed contributions include bug reports, car ports, and any [open issue](https://github.com/commaai/openpilot/issues). If you're unsure about a contribution, feel free to open a discussion, issue, or draft PR to discuss the problem you're trying to solve.
 
-Code is automatically checked for style by GitHub Actions as part of the automated tests. You can also run these tests yourself by running `pre-commit run --all`.
+A good pull request has all of the following:
+* a clearly stated purpose
+* every line changed directly contributes to the stated purpose
+* verification, i.e. how did you test your PR?
+* justification
+  * if you've optimized something, post benchmarks to prove it's better
+  * if you've improved your car's tuning, post before and after plots
+* passes the CI tests
 
-## Car Ports
+### Car Ports
 
 We've released a [Model Port guide](https://blog.comma.ai/openpilot-port-guide-for-toyota-models/) for porting to Toyota/Lexus models.
 
 If you port openpilot to a substantially new car brand, see this more generic [Brand Port guide](https://blog.comma.ai/how-to-write-a-car-port-for-openpilot/).
 
-## Pull Requests
+## Testing
+
+### Automated Testing
+
+All PRs and commits are automatically checked by GitHub Actions. Check out `.github/workflows/` for what GitHub Actions runs. Any new tests should be added to GitHub Actions.
+
+### Code Style and Linting
 
-Pull requests should be against the master branch. Before running master on in-car hardware, you'll need to clone the submodules too. That can be done by recursively cloning the repository:
-```
-git clone https://github.com/commaai/openpilot.git --recursive
-```
-Or alternatively, when on the master branch:
-```
-git submodule update --init
-```
-The reasons for having submodules on a dedicated repository and our new development philosophy can be found in our [post about externalization](https://blog.comma.ai/a-2020-theme-externalization/).
-Modules that are in seperate repositories include:
-* cereal
-* laika
-* opendbc
-* panda
-* rednose
+Code is automatically checked for style by GitHub Actions as part of the automated tests. You can also run these tests yourself by running `pre-commit run --all`.