I have been in a similar situation, and what worked very well for me (just as keywords, just google it or get a book):
1. make the work, priorities and non-work visible through visual management techniques (Kanban Board etc.) -> see Lean
2. explicitly limit parallel work, think of your team as a laser not as a lightbulb
3. talk with your team about how different decisions are made, try to keep the decisions with the experts (them): see delegation poker or delegation board from management 3.0
4. They want to make the right things, really: Think about all information they need to do make the right decisions, (from business perspective, not limitied to tech) and provide them with that. Trust them.
5. remove non-work items. Meetings, calls, e-mails, etc. my most happy and productive current team does not own a phone, and has received less than 1000 mails in one year, including notifications - 8 people.