My general approach to solve coding challenges is to focus on easy and medium level ones first.
To solve the challenge, an array of strings needs to be pushed with new strings and checked that there are no duplicates in the list.
The mechanics for this process can be narrowed down to array manipulation and string normalization.
JavaScript library such as MDN can provide useful information to help solve the challenge.
Hints provided by the coding challenge can also provide helpful suggestions for tackling the challenge.
The Scrimba's Javascriptmas event is an example of easy and short challenges that can aid in boosting confidence in one's coding skills.
The initial code for the challenge only requires to fix a small issue, hence checking the rest of the code for the application may not be as necessary.
There are also stretch goals for the challenge like checking for case sensitivity and adding the functionality to edit/delete list items.
Taking the code from the challenge and turning it into a personal project is encouraged to continue practicing and improving your coding skills.
The article provides a good approach to solving similar coding challenges by understanding the problem, then breaking it down into smaller comprehensible parts and utilizing available resources for guidance.