Many Christians struggle to point to a time when they have seen or felt God's presence in their lives. However, there are a variety of personal experiences one can have with God, and the types of experiences one counts as valid often depend on his or her theology. St. Teresa of Avila, for instance, was a 16th-century Christian mystic who believed she had seen Christ in bodily form. Many Pentecostal Christians claim similar experiences.
You may never have felt Christ's bodily presence--at least in the moment--but you can likely look back on your Christian life and see times when God was with you. Perhaps he gave you strength during a difficult period in your life, or perhaps you narrowly avoided great harm (spiritual or physical) and now realize God was protecting you. Such experiences may not be as sensational as St. Teresa's, but they are no less valid.
Christians are all unique, so it is difficult to explain how one felt or saw God's presence due to everyone viewing or feeling God differently. However, there are common ways many may have seen or felt God. One may have felt God through God's creation of everything. When one looks at the complexity of the nature they are surrounded by it can be hard to simply brush it off as a coincidence and not the intelligent design of a benevolent God. Another way one can feel the presence of God is through the unconditional love of others.
I wish you the best of luck on finding and wording how you may have felt or have seen God.