Creating focus on the subject in your image can be done in many ways. Although, sometimes, as with landscape and architectural photography, your entire image is the focus; as you are trying to convey the whole.
To master focus we can use knowledge of aperture, the rule of thirds and lighting.
Setting your lens to a low F number then placing the subject in the foreground, blurs the background. But, you can also place your subject in the background and blur the foreground to create focus.
Another way to give attention to your subject is to place them on a 3rd in the frame – the rule of thirds is key to the human eye finding an image attractive.
Focus can also be achieved through dramatic lighting on your subject. Tried & true photography fundamentals always work; but the best part is experimenting with your own style and preferences!