To become a good web developer following are the concepts you must know to how to work with

1. Installation and Setup - Setting up framework or finalize directory structure and then setting up database
2. Authentication - Adding user table giving user option to register and login
3. Variables, Data types
4. Functions and loops
5. Date Time Manipulation
6. Crud Operations - Create, Read, Update and Delete are very basic to know for any development project
7. Authorization - Giving your web portal option to create roles and permission so accordingly they can access to only permitted modules/section/elements
8. Data Table - Showing data in table with feature like pagination, sort and filters
9. Notifications - Whenever you want to show notification to user like in webpage also sending notification via email/sms
10. API Integration - Some time you will need to consume data in your application
11. Email/SMS Integration - once you know api integration you should integrate this things
12. Payment Gateway Integration - You should get hands on to integrate different payment gateways.
13. Events - You must know how to create event and listen to event so you can process things in background and this will be very helpful in microservices
14. Reports/Chart- You must know how to create reports using tables also you should get experience in creating pie/bar/line etc charts. Using this you can create good dashboards.
15. Forms - while learning crud you will get this, but you should get hands on all types of inputs.
16. Validations - Server side validation are must client side validations can be manipulated but you should do that too to give good experience to user
17. Import/Export - You should know how to import csv/excel data to database and how to export from database to excel/csv
18. Deployment - Deploying the website to server on cloud or hosting provider. So website can be accessed trough actual domain name.