Sounds like I'm in the same Beginner-Intermediate boat as a lot of people. What I've found really works is first off- learn Hiragana and Katakana. They're both a lot simpler than I imagined. But it will really help with pronunciation if you know the actual letters (symbols?) you're trying to say. Japanese is very different than English in that there is only one correct way to pronounce each letter (consonant-vowel pair? this is a hard term to nail down.)

Also, find a Japanese friend who knows at least a fair bit of English, and talk/write to them. I regularly talk to a Japanese friend on FB in Japanese, and it really helps me learn relevant vocabulary and the correct way to phrase things. There are plenty of sites to match up pen-pal type arrangements if you don't know anyone from Japan.

Finally, have fun with it! If you can take a trip to Japan do so of course, but if not surely you can find a sushi restaurant or izakaya in town, and practice with the people there while enjoying Delicious Japanese Cuisine.