Start by picking out any word in a paragraph and look at it for a moment in total silence. Look at it, and instead of repeating the word mentally, think about what it represents and means. Think about its meaning. You can even just describe it mentally instead of reading it out loud inside your head. There will still be a slight bit of subvocalization, but by merely observing words without the desire to pronounce them, the new habit will begin to form on its own.
