A simple but clear proclamation is the G.O.S.P.E.L analogy
God. The creator of the universe who created us and all things created us to be with him. (Psalm 100:3)
Our nature, which we inherited from first man (Adam), is made plain and obvious in how we mess up in sick cycles of lying, pride, lust, jealousy, cheating and so on. These actions separate us from God who is good. (Romans 3:23)
Sins. The word we use to describe our messy actions that separate us from God. Doing good doesn’t clear our name. We’re a guilty party, destined to be separated from God. There’s nothing we on our own can do about it. (Isaiah 64:6a)
Paying. Jesus paid the price for our mess, he lived as our example, he put our mess on his shoulders, he took our place, died on our behalf, and rose again as our guarantee (Romans 5:8)
Everyone. All who trust in Jesus alone, is forever forgiven of their mess, are destined for a glorious life with God and reassured of eternal life with him. (John 3:16)
Life. This incredible life with Jesus starts right now and on into eternity (John 10:28)
That is the Good news, that is what we all have to respond to.
That is the Gospel.