If you have to go for a Drupal core update from a previous install based on composer_manager or drush (both deprecated), consider installing something robust, Composer friendly, that excludes vendor and core for a lightweight repository and enables CI and automation tools like Phing, Behat, PHPUnit, CodeSniffer, ...
If you don't have Drupal VM installed, head to the documentation.
If you look for ideas to decorate the office, here are my two favorites from Drupal.org
The l() function is deprecated in Drupal 8, here is a starter.
Import the URL and Link classes :
You have several options, but basically, you can start with an url that will be used by a link.
One of the possible implementation will be used, with the Link::fromTextAndUrl method.
Drupal 8 evolves quickly, and it's easy to get lost amongst the several documentations that have been written since the beta releases, Drush and PHP version needs upgrade. Some things that I have learned.
Option 1 : No VM setup on Mac OSX, via Homebrew
Okay, VM's are easier to maintain solutions, but in some situations you just don't have enough RAM for having Virtualbox running all the time.
After trying the latest dev release of VDD (needed to run Drupal 8, because at the time of writing this, the stable release is stucked to PHP 5.3), I decided to give a try to VLAD, another Vagrant alike solution.
Main reasons : git and drush are not already installed on th VDD dev, and sometimes I got stucked on the vagrant provisioning.
First reaction after installing VLAD : Woooooow !
Here are some of the sweet goodies that awaits you :