Fred Sanders offers a number of quotes on the Gospel from his recent book The Deep Things of God: How the Trinity Changes Everything (p. 106). Each of them offers some food for thought on various ways that we present a Gospel that is too small.
A gospel which is only about the moment of conversion but does not extend to every moment of life in Christ is too small.
A gospel that gets your sins forgiven but offers no power for transformation is too small.
A gospel that isolates one of the benefits of union with Christ and ignores all the others is too small.
A gospel that must be measured by your own moral conduct, social conscience, or religious experience is too small.
A gospel that rearranges the components of your life but does not put you personally in the presence of God is too small.