'Two things fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me. I do not seek to conjecture either of them as if they were veiled obscurities or extravagences beyond the horizon of my vision; I see them before me and connect them immediately with the consciousness of my existence. The first starts at the place that I occupy in the external world of the senses, and extends the connection in which I stand into the limitless magnitude of worlds upon worlds, systems upon systems, as well as into the boundless times of their periodic motion, their beginning and continuation. The second begins with my invisible self, my personality, and displays to me a world that has true infinity, but which can only be detected through the understanding, and with which I know myself to be in not, as in the first case, merely contingent, but universal and necessary connection. The first perspective of a countless multitude of worlds as it were annihilates my importance as an animal creature, which must give the matter out of which it has grown back to the planet ( a mere speck in the cosmos) after it has been (one knows not how) furnished with life-force for a short time. The second, on the contrary, infinitely elevates my worth, as an intelligence, through my personality, in which the moral law reveals to me a life independent of animality and even of the entire world of the senses, at least so far as may be judged from the purposive determination of my existence through this law, which is not limited to the conditions and boundaries of this life but reaches into the infinite.'
Axiom: I understand for inner peace to be a state of mind where one is satisfied with the condition of their mind. E.G, the essence of thoughts, feelings, intuitions and so on, as well as the general atmosphere/background of one's sense of self.
Premise: Inner peace is desirable because it is highly conducive to one finding a satisfactory inner identity. The aforementioned is desirable because it will allow for one to maintain a consistent focus in life and allow to be proficient at long-term thought, both of these are highly conducive to happiness.
1)Understand yourself-In order to find inner peace, you must first understand what inner peace means to you. Think of it in terms of how this very idea of inner peace relates to you, not how you relate to some theory of such an entity. Your inner world is the focus, not the outer. Hence, my recommendation for now is learn to do honest and incisive introspection and be consistent at it.
2)Keep a long term perspective- After you have discovered what inner peace means to you, make extra sure that you stay focused on this goal of yours. This should not be just one thing you do in life, it will be the only. Spinoza once advised for us to think in terms of an eternal perspective, as he believed that God is all, and you are part of God, and when you look within yourself, you see God--which is timeless and infinite, you have no reason to worry about what is temporal. Not even death, in fact he advised for death to be the last thing that man should be worried about. This is very similar to what Jesus of Nazareth meant when he advised for others to live not for themselves but for the kingdom of God. To live for what is eternal(God), and not for what is temporary(self). Jesus, unlike Spinoza, was not a pantheist, he believed that the self(flesh) dies.
*Please take note. I referred to Jesus as 'Jesus of Nazareth' and not the Christ. I am not recommending a Christian perspective of inner peace, I am just using his idea as an illustration of an advice to promote the eternal over temporary.
3)Avoid complacency- Continue to practice quality introspection and maintaining focus on the goals that you've discovered and established afterwards.
4)Stay internally focused- This is a very reliable way to avoid complacency. External standards have a very high potential to distract you from your introspection and may force you to focus on concrete,externally founded objectives that can be achieved at one point. In the Myth of Sisyphus, the protagonist who once started off as a naive bliss seeking venturer, hoping to find meaning in his life ends up rolling the boulder up and down to the hill for eternity. For what? One may ask. What has he accomplished? Nothing. And only in external nothingness will one find meaning in life. We will never find a purpose that can satisfy us, this is not possible as that by definition implies becoming complacent. We must find a purpose that we will never be able to achieve, and find solace in striving for it. This will be the greatest joy man will ever find. Whatever goals can be achieved, can be superseded, yet your drive to strive for an unachievable purpose can not be--as it is not subjected to comparison.