To implement a responsive portfolio in Drupal, first, install and enable modules like Views, Image Styles, and Field Formatter Class. Then, create a View to display portfolio items, configure it with responsive settings, and style it using CSS or a responsive theme. Ensure images and content adapt well to different screen sizes for optimal viewing across devices.

To create a SASS-based theme in Drupal, start by creating a sub-theme of a base theme like Bartik or Bootstrap. Then, configure your sub-theme to use SASS by updating the .info file to point to your SASS files. Finally, compile your SASS files to CSS using a SASS compiler like Koala or command-line tools like node-sass.

To install requirements for Laravel 4.2, ensure your server meets the PHP version requirement (5.3.7+) and has the necessary extensions enabled, such as PDO, OpenSSL, Mbstring, and Mcrypt. Additionally, use Composer to install Laravel and its dependencies by running "composer create-project laravel/laravel project-name 4.2.*" in your terminal.

To activate the Laravel Blade syntax highlighter in Sublime Text Editor, install the "Laravel Blade Highlighter" package via Package Control. Once installed, open a Blade template file (with the ".blade.php" extension), and Sublime Text will automatically recognize and apply the syntax highlighting for Blade syntax.