The standard works of the Church are your basic sources for teaching the restored gospel of Jesus Christ. You may also use the words of living prophets. There are many reasons why it is vital to use the scriptures as the basis for your teaching.
The scriptures invite the Holy Ghost into your teaching. They teach God’s word with power (see Alma 31:5).
Your ability to teach with power from the scriptures comes in large measure from the time you personally spend studying them. As you daily feast upon the word, your ability to teach from the scriptures will improve.