Getting to a happy state of mind is a journey. It requires you to reflect on what makes you happy (ie. spending time with your children, walking your dog) and then it requires you to stay present in that experience. So that means you can’t check social media while spending time with your children or walking your dog. Yes, those experiences bring happiness but you miss out on feeling the emotion (happy) when you’re distracted. So what happens is that an experience that makes you feel happy may turn into something stressful (ie. if your children start arguing while you're looking at pinterest and now you find yourself breaking up a fight). What you are then left with is a stressful impression of a happy experience. When this happens over and over, you will start to think that spending time with your children isn’t a happy experience and other emotions set in. Therefore, unless you stay present and become aware of the times when you are feeling happy, you will miss out on it.
One more thing. Because happiness is a state of mind, the goodness that you choose to focus on in your life will contribute to how intensely you feel. The more you focus on positive aspects of yourself and your life, the more you open yourself to feel positive and happy in your life. But this is a state of mind that requires practice. You can choose to pray, meditate, write, or anything else to help you stay in this state of mind. Whatever works for you, stick with it and do it daily this new year.