Practice in your native language. Spend some time repeating word-for-word right along with any material you may need to interpret in the future, such as a short speech. Your practice material should be no longer than 1-3 minutes to begin with, and you should record yourself and play it back to see how close you were.
Notice areas of difficulty. Did you hesitate, stumble over a word, or lose the flow of what you were saying? Also pay attention to the way you speak. Are you clear and easy to understand? Do you have a tendency to speak too softly or too loudly? Is your accent understood by most people you meet?
Work on problem areas until you are comfortable with how you speak and deliver the practice material, then move on to interpretation. You will likely find you will again need to revisit similar areas of difficulty because you are now filtering the material through a second language. Although simultaneous interpretation is a demanding profession requiring a large set of diverse skills, it’s rewards are equally impressive. You get the personal satisfaction of knowing your work makes a real difference to your clients by helping them to communicate and interact in diverse settings. As a simultaneous interpreter, you can facilitate the legal process for non-native speakers, help international businesses and conference attendees communicate and exchange ideas, and help save lives by working with medical personnel in emergency situations.