Writers use bold and italic. But, reportedly, in HTML, that can make accessibility harder. Instead, use this markup:
- — for bold, replace <b>. . .</b> with <strong>. . .</strong>
- — for italic, replace <i>. . .</i> with <em>. . .</em>
The old stuff was more intutive. The new forms are not so much. But if mnemonics could help you, try these: “Be Strong” and “I Am”.