Wired 2007 How To issue is so good, it's full of tips in various topics, so useful and handful. I will be keep posting more as I read. Enjoy.
1. Double up on tasks that use different channels, i.e. writing a report while brainstorming designs for a new logo.
2. Think carefully about the requirements of each task, the actual processing needs may not be what you'd expect.
3. Juggle selectively. Minimize unnecessary distractions, when knowing that interruptions will be frequent, focus on routine tasks.
4. Interrupt tasks at natural breaking points whenever possible.
5. Set aside time when you will not do anything at all. Take breaks, eat well, exercise, and be sure to get enough sleep. IMO, this should be on the no. 1.
Sure, multitasking is often requested in almost all work places and is supposed to improve the productivity but it might make you less productivity in reality. So doing it right without losing your mind is something that we all need to focus on as well.