How to select a project to contribute to?

There are several way to decide if you’d like to contribute to a project.

Project that you use, that you need, maybe even like

Probably the best way to select a project that you really need. That will give you a motivation to contribute to that project. However the problem is that these projects tend to be relatively mature meaning the easy issues are probably mostly solved. On the other hand there are probably more users so more questions to answer.

A project in the field of your interest

Another direction is to find a project in the field that interests you. This might mean the programming language you are already familiar with or the programming language you are currently learning. The framework you are already familiar with or the framework you are learning.

GitHub Topics allows you to filter based on topic and programming language. Then sort by number of stars, number of forks, and the recentness of its update.