There is no real trick to mastering Data Structures that we can tell you here. It's more about practice and experience. Data Structures is not just about knowing about a lot of data structures and being able to code them. It is more about being able to apply them to real problems that you solve. You need to aply the data structure to a problem that makes it easy to solve. This comes by practice only.
You can start with a basic book on Data Structures. I would suggest Coremen. Then after mastering a few important ones you should look to solve problems from online competitions, etc
If you want to master data structures, a few good first baby steps would be to get good at basic data structures in C or C++ (graphs, trees, etc, using a common first text like CLRS or some other), then learn a bit about functional data structures by reading Okasaki and doing some practical functional programming, then watch the Advanced Data Structures lectures on MIT Open Courseware (and do the homeworks). It's probably a good idea at some point to make some relatively data-structure-intensive projects, such as a 3D graphics engine, optimizing compiler for a statically typed language (ideally one that uses unification at some point in type checking), and a database engine (especially if it doesn't rely on kernel page caching).
You're not really a master at that point but those are some good first steps. Then you'll probably have an idea of what to learn next.