I'm absolutely in love with this game. Learning to play guitar or bass has never been more fun than this. All you need is your electric guitar or bass of choice, the game and a cable that you can buy in a lot of stores that sell things related to music or just electronics in general.
When you first start up the game you get to set up a few things just so that you get the most out of your Rocksmith experience. I went with the option of starting out as someone who has never played guitar previously although I did have some knowledge about how to play. If my memory isn't failing me you get to calibrate and tune your guitar before the game lets you continue onwards. The game then explains the basics and how the layout of the so called 'Note Highway' will show you what notes to hit on the guitar. After you've made it through the basics you're ready to go!
At the start menu there are a lot of options to choose from such as 'Learn a song', 'Lessons' and 'Guitarcade'.
As most other people I went with Learn a song instantly because I was so excited to start playing songs. If you chose the option of starting out as a complete beginner the game will take it easy in the beginning by only giving you a few notes now and then. It will feel slow but it was still enjoyable for me. The way this works is that the more notes you hit and the better you do will increase the amount of notes you get on screen. This is called 'Dynamic Difficulty' and is one of the main reasons Rocksmith actually works as well as it does.
I would recommend starting out in Lessons learning some more of the basic stuff like posture, picking and how to use a strap if you want to play while standing up. I think that most people, like me prefer sitting down when playing Rocksmith or they just don't have a strap to stand up. There are a lot of great lessons ranging from the more simple techniques like chords to the advanced stuff like tapping.
Something that a lot of beginners tend to neglect is the Guitarcade, I really think that the Guitarcade is one of the most important features of Rocksmith as the mini-games are fun and help you build up muscle memory that you will need if you want to play the guitar. One of the best mini-games for me is the 'String skip saloon' as it helps you learn to hit the right strings without looking. 'Ducks ReDux' is another important one teaching you the distance between the frets of your chosen instrument.
The most commonly asked question is probably: "Does Rocksmith 2014 really work?"
Yes! It most definitely works. It provides the motivation and fun aspect needed to learn to play the guitar and your favourite songs. If you are thinking about buying this game and your biggest concern is "does it actually work?" then buy it and see for yourself, I can guarantee that you will atleast to some degree improve your playing and general technique.
Rocksmith 2014 has to be one of my favourite games of all time just because of how detailed and enjoyable it is. A function that I didn't even discuss but is a great way to get better is the 'Riff Repeater'. It lets you slow down and practice certain sections of a song or a lesson and really fiddle around with a lot of settings to make it easier for you to learn. Also in 'Session mode' you can jam with AI musicians playing scales at your own tempo and with a lot of different instruments.