Android and Java
The best place to start with any open source contribution is with something that fits your area of interest. If you have an Android phone, or you're interested in developing code that needs to run on the JVM, VOC is a fantastic place to contribute. In order for VOC to function, all the functionality of CPython that is implemented in C needs to be re-implemented in Java. As a result, there are lots of very approachable and well-contained tasks suitable for first time contributors.
See the guide to your first VOC contribution for more details.
Again, this results in lots of very approachable and well-contained tasks suitable for first time contributors.
See the guide to your first Batavia contribution for more details.
One of the best ways to contribute is to make sure our introductory and tutorial documentation is rock solid. Pick a project of interest from the BeeWare suite, and try to follow the getting started guide and tutorial. If you can't find the getting started guide - then that's the first thing to report!
As you work through the tutorial, take note of anything that doesn't make sense, or doesn't work. Then open a bug report for those problems.
If you're a Windows user, BeeWare can definitely use your help. The core team all use Linux and macOS in their daily development, and as a result, it's really easy for Windows incompatibilities to slip in. This is almost always due to an oversight. Identifying - and maybe even fixing - problems with running BeeWare tools on Windows is an immense help.
Do you speak a language other than English? At present, the core team are all native speakers of English. Providing translations of documentation, or completely new tutorials or guides in your native language is a great way to contribute. Pick a project that already has documentation and translate that text. Alternatively, start from scratch and write a completely new tutorial.
If you speak a language with a non-latin character set (e.g., Russian or Chinese), or a language with a right-to-left script (e.g., Hebrew or Arabic) you'll be able to point out all the places where we've assumed simple ASCII encoding or left-to-right conventions. Pick any of the active BeeWare projects, and try to use it with using your native language. If you hit any problems, report those problems as bugs; if you are feeling particularly adventurous, see if you can work out how to fix the bug, too.
So you want to contribute to an Open Source project? VOC is a great place to start.
So you want to contribute to an Open Source project? Batavia is a great place to start.