Either of these ways:

• Go to the TV Show Index. Select any shows you'd like to follow by clicking the show title. This opens a menu of follow settings. Set your follow settings and click Follow for each one. They'll then show up on your customized homepage. You can also remove or update your follow preferences on any shows from that page. A link to it appears at the bottom of the Customized Homepage. 
• On any topic, at the top click the blue bookmark/flag icon and change your follow preferences. You can follow or unfollow topics here.