Save yourself, use version control
I only carry one strong opinion for software development and that is using Git for Version Control. You should install it on your local machine and practice how to use it on your projects. There are several well-written tutorials and cheat sheets on the internet so go find one that fits your needs. Third Party Hosting is also available and comes up often enough to merit a mention.
Why Git?
When I got my first software developer job, I had no idea how to make sure changes I made in the project didn’t affect anyone. I also didn’t know how to keep track of the changes I pushed. So you can imagine my surprise when I found out there was a tool for that and more. It even makes time travel possible in the project!
Git helps you keep track of all the changes made and takes the burden of having to remember it all so you can focus on solving problems.
How did you practice?
Learning the basic commands on the command line or finding a friendly graphical user interface client is the best way to practice. There is no right way learn Git. If you’ve never had experience with the command line, the GUI is a great way to learn the basics so when you are comfortable enough you can the command line a try. But you can totally get away without ever having to use it.
Practice makes perfect
Don’t forget to git commit those changes.