Set eye level
A good photograph of people is always taken at the exact eye level or slightly lower from the eye level. Until or unless, you are going to take picture of sun, moon, stars etc, you should not take pictures of people above your eye level. When taking a picture of a couple or group of people, you should kneel down and take the picture.
Take help of autofocus
Most of the cameras nowadays have autofocus function installed. Therefore, you must ensure that it is turned on before you take the picture. The autofocus function helps the photographer as he just has to include subjects in the focus while the lens will detect faces itself.
Use of flash
You must also increase the use of flash whenever required. For example, when you have ample of daylight, you will not require the flash function. Similarly, if you are taking the picture outdoor, then you might need the flash but if you are taking a snap in indoor facility or at night, you will definitely need help of the flash function.
Avoid lighting at back of the subject
If there is ample light at the back of the person, it will be impossible for you to take a clear picture of the subject. Therefore, it is strongly recommended that you make sure that the sunlight or room light is at the back of photographer as this will help you in taking a clear picture.
Avoid busy backgrounds
You must make sure that the background behind the people is not too busy. If it is, then you must change the background and choose a subtle one.
Take vertical pictures
You should also take vertical pictures of people especially if they are solo or in couple. You must give them some variety by taking pictures from different angles.