Meditation is the most useful tool to elevate Kundalini. But many people are not able to decide - on what Chakra they should meditate or they keep changing the Chakras without awakening any of these Chakras. Actually, this is not a problem at all if you practice the yoga in an organized manner. You won't face this problem if you will practice the previous step of meditation i.e. Pranayam thoroughly.
Proper practice of Pranayam will lead you to know your actual position – on what Chakra your consciousness is lying. Your Prana (Vital force) can be at Muladhar or at Vishuddhi or at Ajna Chakra – it is depended on your past spiritual practice – if you did a lot of Sadhna (spiritual practice) in your previous birth, your consciousness will be situated at higher Chakras and vise versa.
After some practice of Pranayam, you will start to feel the sensation of Prana at some particular point in your body. This is the right point or Chakra where you should concentrate your mind on. It's the point where your Prana is lying at. In reality, Pranayam and meditation are not completely distinct spiritual exercises. Meditation is the advanced stage of Pranayam. Even after a little practice of Pranayam, you'll be able to see the light of a particular color at a Chakra. These colors have different meanings which will be discussed later.
It is not necessary to try to fix your mind on a Chakra forcefully. You won't be able to concentrate if you'll try to do so; because you don't know the right Chakra for you. It'll be a wasteful effort. You will enter in meditative state automatically while doing Pranayam. Pranayam is as important as meditation, so don't neglect Pranayam if you want to progress in Kundalini Yoga.