[bread_baker]

I think there are 2 situations: vocabulary you plan to teach, and vocabulary that just pops up, that you didn't plan to teach. For planned vocabulary, I use pictures or realia whenever possible. I show the students the word and teach pronunciation. As PJD pointed out, things are different for incidental vocabulary. I don't worry if the students learn the pronunciation before the meaning. Usually in a few minutes they understand the word and can pronounce it.