Happiness is not the same as inner peace. But the truth is that many people think or say, "I just want to be happy," when what they really want (and if they'd introspect they'd know this) is more inner peace. The world is smaller now and we are bombarded on all sides with so much advertising, unwanted information, and imagery that our ability to be peaceful inside has gotten more challenging. It's not your fault!
Happiness does not necessarily bring more inner peace, yet more inner peace will almost always allow us to be happier.
How do we get it?
The first thing some sages recommend is to understand what mankind is.
What is mankind?
Life is meaningful and not random. We were created for a purpose and we are connected to the source of life. We don't recognize our oneness with the Creator, so we get confused and distracted by the world at large. We are a creation of the Almighty who has a purpose and destiny for mankind. To attain inner peace we must first be convinced of our meaningfulness and purpose. I can't do this for you. I can only direct you to the ideas that I am convinced of. You have to think about this yourself and be convinced yourself.
To paraphrase a wise statement I once saw - Just as a wind cannot whip through a junkyard and create a 747, so too and all the more so, this grand amazing universe could not have happened randomly.
To feel like you have a grasp on the reason for your existence is one of the most settling things possible. When you think it through and become convinced, calmness will envelop you. It won't solve all your problems and challenges. It may even create more and different challenges for you. But inside you have a direction and purpose now. It is what your soul desires. You might still be mad at your parents, children, spouse, or boss. You may be troubled by war and famine. (As you should) Heck, you might be at war with the entire world, but you will be at peace with your soul.
You are a soul
Wading through the muck and mire of the physical world will always be dissatisfying. No matter how much money a person has there is no peace without spirituality. This is so because the body gets something out of the physical world but the soul doesn't. Does your soul eat pizza? Sit on the beach? Go out to a movie? The soul is spiritual and only gets pleasure from spiritual things. A meal is delicious but only lasts for 20 minutes. If you thank the provider for the meal, though, you add a spiritual element that elevates the entire experience, and thereby include the soul.
Inner peace on a daily basis requires many tools and much inner development. The first step is to identify the needs of the body, and to identify with the yearning of the soul. The body wants pleasure, comfort, and rest. The soul yearns for wisdom, meaning, and good deeds.
Step One: Know why mankind is here.
Step Two: Understand the relationship between the body and the soul.