Question: I want to develop a WordPress theme similar to another theme present on the internet. Shall I use the default WordPress theme to start from or start from scratch? 

Please guide me.

Answer: 
Use [this](http://underscores.me/) basic theme with default features that should begginer person to know.

* A just right amount of lean, well-commented, modern, HTML5 templates.
* A helpful 404 template.
* An optional sample custom header implementation in inc/custom-header.php
* Custom template tags in inc/template-tags.php that keep your templates clean and neat and prevent code duplication.
* Some small tweaks in inc/extras.php that can improve your theming experience.
* A script at js/navigation.js that makes your menu a toggled dropdown on small screens (like your phone), ready for CSS artistry.
* 2 sample CSS layouts in layouts/: A sidebar on the right side of your content and a sidebar on the left side of your content.
Smartly organized starter CSS in style.css that will help you to quickly get your design off the ground.
* The GPL license in license.txt.

Use it to make something cool.
For learning & understanding I think you should start from [wordpress blank theme](https://wordpress.org/themes/blankslate/)