I am letting it go some tips I wrote for the hacking day that can help you getting warmed up.
Hacking day is going to be an opportunity to push work from repositories like FriendsOfSymfony, Symfony-CMF, Silex, Composer, Doctrine, Documentation, to even teaching community how to Contribute. This Hacking Day is going to rock!
If you haven’t participated in the early probing please do so now from the above link:
We encourage you after having checked any interest above for a particular repo, to jump onto github and start getting acquainted with:
– how github issues/pull-requests work
– issues labeled as easy-picks, some-component-name, some-release-milestone, etc
– issues descriptions and priorities
– issues that are not confirmed bugs or have no tests
– issues blocked for years and issues recently posted
Help reproduce: Work on reproducing the observed issue with a clean Symfony Standard (SE) installation pushed to your fork of SE. If it has failing test exhibiting the issue created by you would be outstanding.
Help clarifying: This is to help establishing proper descriptions and to have a very clear understanding of the problem. Some tickets created are support tickets and are easy to solve or should be referenced to be treated via the mailing list.
Help escalate and relate issues: If you see a bug that is not yet reported as such somewhere then please create it and notify in the description that needs attention because you think is serious. Sometimes issues are related or duplicated, because they are so many you can help us identifying and verifying that the issue has duplicated tickets, link them or import the information to the earlier reported so we can close the one is duplicated.
Start easy: If you are on the tab of issues or the list already sorted for you always start from the easy end and work your way up. If someone has taken the issue then skip it, if it cannot be reproduced after an attempt then move up to the next, if it is challenging then pair up and clear that is worth working on it; there is always that weakness in an issue that you can start from. Ask @fabpot, @stof or someone knowledgeable and they will point the possible options or plans for attack. We will try to have digested plans of attack for the hacking day so this can be ready for you to work or pair up and accomplish.
Focus on one thing: Tickets can be large or have short scope, always take the smallest unit of work and focus, make assumptions and leave out complexity asap, you want to solve the issue, not the issues, plural. Clean up code and submit about solving one thing only.
Let the review team review: We may have a team to review CS and clean code on PRs submitted. Do not worry about the beauty of your code, it will be reviewed, but rather work out the PR such that it has all comments or details to be further improved, any assumption or tests not written or half written. Leave it easy for the reviewers with a good description so that it can be properly reviewed. Then jump to another issue.
Time does not matter as much: Don’t care too much about time, more important is to understand things and exit the doors with a very clear understanding how to contribute to the repositories. If you do then you will have more time later on to do so. The thing is to lower the contribution barrier. To lower it means more active repositories, more bugs solved, more interesting ideas implemented, more security fixes, higher quality of code, more eyes more reviewers, more support, and more features.
Stick to your team: Most likely you will learn a lot and get to know one or more top devs within your team. Follow their lead, learn more about the repo, help support it, help contributing and gain experience, not only will be good for your resume, but it will be a friendship the whole community will appreciate. A long term contributor is well known by the repo members. It is a special feeling 
.
Help others: If you see someone struggling then help the person, everybody around you is supposed to do the same thing with you or with anybody.
This is your chance, don’t miss it! Whether you are remote or local, we can learn a lot that day!
Encouragements in all good,
your friend @cordoval