Generally to gain root access on an Android device, you will need to unlock its bootloader. While the steps are pretty simple, it is an added inconvenience for newbies. Every once in a while, a developer will find an exploit in Android or an OEM firmware that allows for easy root access to a variety of handsets without the need for unlocking the bootloader.

Based on one such exploit is the Easy Rooting Toolkit from developer DooMLoRD. The exploit will allow you to gain root access on a wide variety of devices, majorly from Sony, including the Xperia Z, ZL, T, P, SL, Go, S, LG Optimus G and the Nexus 4. The toolkit works on devices with a locked bootloader as well, thus saving you the hassle of unlocking the bootloader of your device.

The tool is capable of rooting the supported devices in nearly one-click. The only pre-requisite to using the tool is that you must have the necessary ADB/Fastboot drivers installed on your Windows PC. You can download the Universal ADB drivers from here, which would do the job just fine.

You can find the whole list of supported devices, the download link for the toolkit and other information over at this XDA thread.