Ubuntu 14.04 LTS (Trusty Tahr) is a very good operating system but, like most Linux distributions out there, it's far from what users might call an optimal setup. There are numerous reasons for this fact, but we can detail a few steps that will make your Ubuntu experience increase a great deal.
Even though Ubuntu is a good operating system and the latest incarnation of it, 14.04, is one of the best made so far by Canonical, most users will find that some aspects of the OS can be improved. A number of actions are actually necessary if you want a complete experience.
For example, right after you first start the OS, you will have to open Software & Updates and make sure that all the options in the first Ubuntu Software tab are checked. You will need these repositories activated if you want to have access to the all the important packages.
sudo apt-get update
sudo apt-get install ubuntu-restricted-extras
After the installation has been completed, you will also need to get rid of Empathy, the default messenger on the system. It's part of GNOME and it's actually a very limited and buggy solution. You should install Pidgin instead. Here is a list of commands that will do all this:
sudo apt-get remove empathy
sudo apt-get install pidgin
sudo apt-get install pidgin-plugin-pack
Now, if you are done with the messenger, you will need to install the drivers for the video card. If you have an Intel GPU, you don't have to do anything, but if you have an NVIDIA or AMD solution, you might want to get the proprietary drivers, which offer much better performance in games. Open Software & Updates again, click on the last tab called Additional Drivers, and select the driver you want. It will take some time, but you must be patient. Reboot.