Offline, your business success is measured by location - in other words, your business must be located where people amass looking for what you have to sell.
Online, it's no different. People are looking for information. They "go" where the information is, and you as a webmaster own online real estate. Your website.
Your website content must be full of specific, focused information. If your desired visitors are "everyone", you will fail. You must decide what you are offering to whom, and create in-demand content for those people. Once you have the content, you will get listed highly by the search engines and the traffic will come.
Once on your website, your content must PRE-sell you, your business and, ultimately, whatever your visitors have the opportunity to purchase on your website.
Your perfectly constructed, targeted focused content is a perfect venue for Adsense ads. The Adsense code on your perfected pages will pull up targeted ads for your visitors every time.
But maybe your page has a variety of information on it and you want to emphasize a certain part of it to focus the Adsense ads. Google has something called "section targeting" that you can use under certain circumstances.
You need to be familiar enough with html to add certain code to your site source code, and the sections you want to target need to have a large percentage of your overall page content, enough that Google can understand what you are targeting. You add to the beginning of the section you want to target, and at the end of the section. Google will decide if this section will make you more money, so if it won't, you won't see any change in your ads. Also, it can take up to a couple weeks to see a change.
This technique is particularly useful in blogs, where Adsense ads have an uncanny knack for picking up on terms you don't want it to use.
It's very simple, but not "easy", to build that content rich website. We're not talking overnight success story here. But a long term income built on honest, solid principles that have stood the test of time is nothing to shrug off.
Build it and the Adsense ads will come.