Big ideas fail and fail mainly due to the poor team composition. Almost everyone who has gone through the world of start-ups has experienced or heard stories of great ideas that failed because the team did not have a harmony of both knowledge and character. But what makes a team capable of leading an idea into a successful product? In general, it can be considered that if: the team members have previously worked for other companies, have a good knowledge of the product and possess the necessary skills in this area then the chances of success increase. Another dilemma faced by many new startup founders is whether you should rely on a co-founder or an employee. Once you have recognized that the team needs support how do you manage it? How do you decide if the aid you need should be covered through associates or employees? An important factor in making this decision is the combination of significance, commitment and time. Furthermore, another important factor when building your team is to be sure to avoid hiring people who will not work well together. Finally, we present the 3 must-have roles for a successful team, as well as some conclusions and good practices that emerged from the study of real cases.