Apple, one of the most successful and profitable companies in history, has a method for their major projects: DRI (Directly Responsible Individual). In short, no matter the size of a team working towards a common goal, there is always one, single person who is responsible to see it through. If something succeeds greatly, it's thanks to them. If it fails, the weight falls on them as well.
This may seem like an extreme practice, maybe one devoid of grace. But in my experience, unless it's abundantly clear who is in charge of executing a task, balls will be dropped. Miscommunication and blame-shifting will muddy the waters, and when the smoke clears, no one will know why the project failed.
Being the DRI is a daunting task, one that inhibits many able-bodied leaders from charging forward. It is definitely a risk, but one with great reward. Be confident in your goal, surround yourself with talented, hard-working, and trustworthy people, and being responsible becomes a joy.