Hi icesar.
No matter what business you choose to launch, since you're interested in learning more about business partners, I highly recommend "Mentored by a Millionaire: Master Strategies of Super Achievers" by Steven K. Scott
He covers 15 points which help to explain his own business success, including how to evaluate prospective business partners. This book is entertaining and reminds you that making mistakes and learning from them is a key component to creating your own business success. For the first 10 years of his working life, Steve hadn't held down any job for more than 9 months and his salary was still below many entry level salaries. Read about his engaging learning process and find out how he rose above this.
"There are two ways of meeting difficulties: You alter the difficulties or you alter yourself to meet them.” -Phyllis Bottome