I recommend setting up conversion tracking before you run any AdWords campaigns so that you can properly measure them right from the start. Rather than optimizing for just clicks, you should optimize your campaigns for conversions or visitor actions that you care about, such as sales or leads.
First, decide what actions you'd like to track on your website. For many online businesses, sales is the end goal. However, you could track a variety of other behaviors that signify engagement, such as lead submissions, whitepaper downloads, sign ups, and views of key pages.
You can also track multiple conversions in AdWords by creating separate conversion actions in your account.