Live out what you preach
This will make you a genuine preacher. Generally, people tend to be more attentive to genuine preachers. For myself, in order to satisfy this important point, I tend to live out what I want to preach first before I preach it. In this way I get two things in my favour:
I am able to test that what I am about to preach actually works! I test everything that God shows me to make sure that it is authentic. When it works, I know that it is from Him, and it is of sound doctrine.
By testing things out, I experience miracles & testimonies that I can incorporate into my sermons, and I use these miracles and testimonies as practical illustrations on how the message of the sermon can be applied in everyday life -- and to show that the Word of God really does work! So often people struggle to remember sermons, never mind apply them in their lives. I find that people remember practical stories much easier than they remember pure theories. Testimonies also make the sermon real, and people are then better able to relate to the sermon and to the preacher.
16 Jesus answered, “My teaching is not my own. It comes from the one who sent me. 17 Anyone who chooses to do the will of God will find out whether my teaching comes from God or whether I speak on my own. 18 Whoever speaks on their own does so to gain personal glory, but he who seeks the glory of the one who sent him is a man of truth; there is nothing false about him.