The best way is taking a training course: http://www.qlik.com/services/training/qlikview-training. That will get you up to speed as quickly as possible.
If you want to do it on the cheap then buy and read these books (in the order listed):
- QlikView 11 for Developers - QlikView Book
- QlikView Your Business
- Mastering QlikView
- Qlikview Server and Publisher
- Creating Stunning Dashboards with QlikView
If you want to do it still cheaper (and slower) then
- Read all the blog posts you can find on the blogs listed here: http://www.askqv.com/blogs/
- Solve as many of the problems posted by other users on this community site as you can find time for.