2. Hack it together
3. Go to #1
The only way to improve your skills at something is to practice doing it. When you hit something you don't know how to do, look it up on Google or ask a question on StackOverflow (make sure to search first though). Eventually, after many, many failures, you will succeed.
Make sure that the projects are relatively simple. Think calculators, drawing smiley faces, etc. Increase the challenge of each project, but DO NOT try to build the next Google (at least for a year or two).
http://greenteapress.com/thinkapjava/
http://download.oracle.com/javase/tutorial/
PDF: http://download.oracle.com/javaee/6/tutorial/doc/javaeetutor...
If you start remembering parts in detail, skim those sections.