Following these steps will leave you with a very energy efficient bitcoin miner, as a Raspberry Pi only uses four watts of power, and a miner is typically 2.5W. Mining used to be done with computers consuming over 700W for the same process so to make a jump in savings helps repay the cost of the hardware we are using.
All there is to do now is to sit back and watch the money slowly build up. Though it is important that you understand that Bitcoin value fluctuates wildly, it is extremely volatile, so invest at your own risk.
You can also put up LCDs. Connect more Pis for getting better speed :D
For more information there are a number of websites and forums available, such ashttps://bitcointalk.org/,to help get you started.