PHP, JavaScript, JQuery, HTML
What method do you use to remember? For example; i switched from JavaScript to JQuery and now i forgot JavaScript?
If i could remember, i'd be way more efficient with coding when switching languages. If i decided to start coding in Python, i'd bet i'd forget PHP.
The most important thing is simply going back to the basics, breh. The same thing they made you do back in grade school. Write EVERYTHING (all of the important concepts you need to remember) down in a notebook. Most people have gotten away from doing that...but it worked for me.
But step-by-step, this is what I do:
(1) Get the programming book I want to learn (For instance,
Heads First C#).
(2) Download the software I can use to practice in while I'm reading. (For instance, when learning C#, you need to download Microsoft Visual Studio).
(3) As I'm reading, I write down the most important concepts I come across in a notebook (this helps me remember and comprehend what I'm reading), and I can also refer back to it whenever needed.
You also need to learn programming languages that build upon each other...
The first thing I learned was SQL. By learning SQL, I learned what different data types were (CHAR = Characters, INT = Numbers, etc.) and how to write commands. Then I learned PHP (So I can learn how to get my SQL databases and tables onto the web), then I learned Python, and then C, and C#, etc. To me, each of these kind of just flowed together well in the order I learned them.
Also, whenever I needed a quick refresher in something I had previously learned, I just went back and looked at the notebook I had written all of my notes in. This made it easy for me.