Practice, practice, practice. I'd suggest finding source material to practice, so you can get a feel for how the language flows while you're at it. 

If you can find a book aimed for a lower target audience, perhaps elementary school aged, even if there is kanji written, a lot of them will have the furigana above them, so you can just read those. The added bonus is if you read the kanji first, then read the furigana if you don't understand it, that way you get to practice both. 

Another suggestion I can think of is installing [rikaichan][1] for Firefox, or another such [browser addons][2], and find a Japanese website that you want to read and just keep mousing over the kanji you don't know. The same thing goes for trying to read the kanji.

I'd also highly suggest reading everything out loud (circumstances permitting). That way it gets cemented better in your brain, it keeps you honest (you can't skim over the tricky parts) and you get pronunciation practice as well!

Keep at it, and you'll get it over time!


  [1]: https://addons.mozilla.org/en-US/firefox/addon/rikaichan/
  [2]: http://meta.japanese.stackexchange.com/questions/756/resources-for-learning-japanese/757#757