Here are some of my mistakes:

1. Writing Code Multiple Times

2. Folder Structure

3. Existence of Library

4. Variables

5. Googling

Writing Code Multiple Times

The purpose of programming is to avoid doing tasks multiple times. So instead of writing a functionality multiple-time make a reusable function.

Suppose a project has an upload function that uploads an image to the database. And we write down the whole functionality multiple times in each API.

Instead, make a single reusable function and call it wherever needed.

Folder Structure

Folder structuring will help a developer in long-term maintenance.

If a project is transferred to another developer, a good folder structure will help a developer to understand the project smoothly.

Not to worry if you don't know the folder structuring because with experience you will gain knowledge.

Existence of Library

Some libraries help you to avoid code-custom functions.

Example: Instead of writing an upload functionality manually a module would be more effective and it will save time.

So next time, before implementing a feature (functionality) just search it online if any module is available for that particular task.

Variables

We use many variables in our project and define them in each function. But some variables are the same throughout the project like the global variable for a project.

I use to initialize these global variables in each file. But when I'd to change these global variables, I would have to change them in multiple files.

All these global variables could be defined in a single file and then could be imported where required and in that way, it would be more centralised.

Googling

Before taking help, try to search for the solution by yourself. The problem you encountered has probably occurred to someone else and has already been resolved.

If you are trying to learn a new feature, its tutorial is also available for free online. I learnt about it in my internship because nobody taught me everything like in school. Instead, they gave me direction to learn by myself.

The tech community is giant and helpful. And now you are also part of it.

Welcome!