There’s quite a lot of information in the OSM wiki at https://wiki.openstreetmap.org/wiki/Google_Summer_of_Code. Obviously that’s “up to last year” (nothing has been planned for 2023 yet), but some of the advice is still good, for example “Students … should familiarise themselves with OSM by creating an account and improving the map by making some edits in their local area” from this page.
To expand on @SomeoneElse answer; not only hasn’t OSM made any plans for a GSoC 2023; google hasn’t even announced that there will be a 2023 edition. Now while that is likely to occur what it will actually be like is way out there (I would bet on essentially all changes they made for 2022 being rolled back, but who knows).
Of course, the next step is for OSM to apply to be a mentoring organization again. I expect preparations to start in earnest in early January. But if someone reading this is a member of the OSM developer community interested in becoming part of OSM’s GSoC admin team, feel free to already let us know. Additional help will be useful given Sarah’s new responsibilities as an OSMF board member.
As for people interested in participating as a student/mentee, I think it’s still a bit early to get into specifics. But I support @SomeoneElse’s tip to start getting involved with OSM in general.
I have several experiences in mentoring young developers to develop OpenStreetMap-based project. For example, several month ago, me and my team developed cempat.in (OSM-based story sharing platform) as a team project to learn more about OSM and web programming in general
Missed that. Seems however that google has made it even less clear than this year who will be eligible and what the point of the whole thing is, that’s quite a feat.
It’s good to see so much interested in GSoC already. It’s always good to have an early start, even if the orga isn’t ready yet. I’ve put up a little summary up now over on Google Summer of Code - OpenStreetMap Wiki for everybody already interested. Here is a copy for your convenience.
Google Summer of Code 2023
The OpenStreetMap org will start preparation for the 2023 edition of Google Summer of Code at the beginning of the year. Please watch the forum for an announcement of the official start.
Students
If you are a student interested in participating, please use the time to familiarize yourself with the OpenStreetMap project:
Create an account and start contributing data. Get to understand how tagging works, what data there is in your neighborhood and how to update and complete the map.
Find out where your local community meets and get in contact with them. Start to follow discussions on the forum.
Work with the software using OpenStreetMap data: editors, renderers, search, routing. We are an umbrella organisation for many projects around OSM. Try to get an understanding what exists and find out which part interests you.
If you already have a project in mind, you can also get in touch with maintainers of the project directly. See if you can already help out with small tasks to get an idea how the project works.