Every programming language has the same set of features more or less. If you know at least one programming language then getting familiar with other languages will be easy.
Starting with basics is always important as it is essential to get familiar with the syntax. Which includes:
- data types
- conditional statements - if, if-else, switch.. etc.
- Loops - while, for, etc.
Learning one time would suffice.
Several language-specific frequently used features. Which includes:
- String and methods
- Arrays and methods
- Date and methods
Practicing several examples and several times make you an expert in using them.
Building blocks of language. Which includes:
- All about Functions
- All about objects
- Handling DOM
- All about JSON
Getting the concept of these items is very much important. Learning and practicing with simple examples for 1-2 times enough. You would easily grasp what each one does as per its context.
Knowing internals. Which includes:
- Browser APIs
- Web APIs
- Memory handling
Go through them once and keep in mind what each topic does.
Keep practicing below items
- Array methods
- String methods
- Date methods
- Regex methods
- Math methods
There are couple more things we usually have to follow:
- Trying any programming paradigms like functional programming
- Going through interview questions or programming examples
- Doing simple projects
Do follow only one website or tutorial or youtube channel where all these contents are covered.
Going through each of them in order will be very much helpful.
All the very best.