Measuring the Distance:
One of the easiest methods to use manual focus is to measure the distance from your camera to the subject, and then adjust your focus lens’ ring according to the total distance. The following method is best to use if you are using a tripod for taking pictures and your subject is in an idle state.
In-Camera Focus Sensor:
If you look closely the view finder on your camera, you will see that there is a tiny little circle with two arrows on it. Whether you are focusing manually or using the auto-focus feature, the little circle with two arrows will let you know when you have achieved focus perfectly.
Most of the beginner level photographers prefer using auto-focus feature due to the fact that almost every DSLR camera does not have good view finder as compared to the old SLR cameras. In addition, these modern cameras’ view finders are very small, and it is hard to determine that they have focused perfectly or not. The solution to this problem is to attach a focusing screen to your camera. It will not only enhance your view finder but also make it a bit easier to determine whether you are completely focused or almost focused.
Setting your focus to infinity will help you taking perfectly focused pictures of landscapes. If your subject or landscape is too far away then setting focus to infinity will make them in focus, as objects that are too far away from the camera lens are considered as infinity.
If you know that the object you are going to shoot will be exactly at a certain point, then one can pre-focus the camera with the help of the auto-focus feature and then refine your tuning by switching to manual settings. This method is very helpful for shooting in the studios.