Update README.md

Author: ocots

README.md

@@ -23,9 +23,14 @@ The control-toolbox ecosystem gathers Julia packages for mathematical control an
 
 ## Contributing
 
-If you think you found a bug / an error, or if you have a feature request or suggestion, feel free to open an [issue](https://github.com/control-toolbox/preconditioning/issues).
+[issue-url]: https://github.com/control-toolbox/preconditioning/issues
+[first-good-issue-url]: https://github.com/control-toolbox/preconditioning/contribute
+
+If you think you found a bug or if you have a feature request or suggestion, feel free to open an [issue][issue-url].
 Before opening a pull request, start an issue or a discussion on the topic, please. 
 
-Any contributions are welcomed, check out [how to contribute to a Github project](https://docs.github.com/en/get-started/exploring-projects-on-github/contributing-to-a-project). First good issues, if any, may be found [here](https://github.com/control-toolbox/preconditioning/contribute).
+Any contributions are welcomed, check out [how to contribute to a Github project](https://docs.github.com/en/get-started/exploring-projects-on-github/contributing-to-a-project). 
+If it is your first contribution, you can also check [this first contribution tutorial](https://github.com/firstcontributions/first-contributions).
+You can find first good issues, if any, at the [first good issues page][first-good-issue-url]. You may find other packages to contribute to at the [control-toolbox organization](https://github.com/control-toolbox).
 
 If you want to ask a question, feel free to start a discussion [here](https://github.com/orgs/control-toolbox/discussions). This forum is for general discussion about this repository and the [control-toolbox organization](https://github.com/control-toolbox), so questions about any of our packages are welcome.