Meditate on a question and when you are ready ask away. Try to be as specific as you can. e.g. What will happen if I do x?
Your interpretation is key. Think about Shenron as a very old man, talking from experience, only to guide you make the right choice. Are you ready? Yarrow Stalk method is used to cast hexagrams. Do not ask Shenron the same question more than once. Only the first answer is valid.