I went through part of the first lesson of Erin's Challenge, suggested by devilyoudont. It seems like a pretty good resource, though it does demonstrate how far I still have to go as well.
Here's one line in the advanced skit that I puzzled over, which shows how hard Japanese can be.
*listening to skit*: Ken warned Erin to "be careful" about something about Saki, but I couldn't understand what.
*reading the script*: けんた： おこらせるとこわいから気をつけてね
so that's wake up - toko? - wai? - kara=from? - be careful
Kenta ： Erin, you have to watch out for her.
Kenta ： She's pretty scary when she's mad.
<- Huh, that is not at all what I thought it said. Better go back and look again
* Oh wait, おこらせる probably means "to get angry", not "to wake up" like I initially thought. (it turns out that's oKIru not oKOru, something I often miss on WK. Why do all Japanese words have to be so similar sounding?
* so we have get mad - toko? - wai? - kara - be careful
still doesn't make much sense
Oh wait, that こわい is kowai (scary)
get mad - and - scary - from - be careful
と usually means "and", so it still didn't make much sense, but after pondering it for a while, I vaguely recalled that と can also be used as a conditional. And kara also expresses the reason for something. So we finally have
[get mad] -> [scary] therefore [be careful]
Come to think of it, the らせる in おこらせる looks like causative form, although I'm not familiar enough with all the advanced conjugations to be confident about that. So maybe it means "if you make her mad, she is scary, so be careful".
Anyway, that was more or less my thought process. It shows how even with the English translation given, it still took me a long time to understand the sentence. Why does Japanese have to be so hard?
It also shows that reading a lot about grammar doesn't help much with actually applying it, although without all my recent grammar study, I probably would have never even remembered those rules in the first place.