Getting a visitor to your website is only half the battle. How do you keep them? A lot of attention is put on the "action" items on a homepage, but it's more likely a visitor is landing on an interior page from a Web search or link. Every visual element, content or cue makes an impression with your visitor and influences what next step they take. The last thing you want to do is leave your visitor at a dead end or continuously force them to use the back button. With each page having a defined next step it gives your visitor a forward moving Web experience.
The idea is more than just bigger and brighter action buttons. No matter how large you make them your visitors are not going to click if they don't care. Your goal is the design an experience to make your visitors care.