You could practice by yourself by reading out loud. I really should do that again myself, too - I have the tendency to speak too fast, and not pause enough for breath, which leads to me *gasp*ing for air a lot. Try to relax and pay attention to your breath. It's a bit weird speaking aloud by yourself, but I think it helps. If you're braver than me, you could even record yourself and listen back, to hear how you'd sound to others.