The amount of twinkling depends on a number of factors, including the star's brightness, its altitude above the horizon, and the state of the Earth's atmosphere. Brighter stars twinkle less than fainter stars, because they are more easily visible through the atmosphere. Stars that are lower in the sky twinkle more than stars that are higher in the sky, because the light from lower stars has to pass through more of the atmosphere. And stars twinkle more on nights when the atmosphere is turbulent, such as when there is a lot of wind or rain.
The twinkling of stars is a beautiful and fascinating sight, and it is one of the things that makes stargazing so enjoyable.