I was engaged in discussing inspiration with those who found the idea of making important decisions based on inspiration laughable, even repulsive.
And doing so I was struck with the importance of keeping the commandments. I could hardly tell such people "listen to the Holy Ghost." I don't think they had ever met.
But what can you tell such people?
Well, the answer is found nicely the example set by ancient prophets. When people are willing to listen then the prophets talk more about listening to the Holy Ghost. They speak about heavenly things. But when people are rebellious, the message tends to be more blunt and direct: "repent and keep the commandments". I guess the more complete version is "repent and keep the commandments that the Holy Ghost can have place in your heart".
And that is the key. We need to prove that we will submit our will to the will of our Father by keeping his commandments. We need to have a broken heart and a contrite spirit, as measured by our willingness to follow Christ's example and submit our will to the will of the Father.
Until we do that, the Holy Ghost really can't stay around.
The general principle is the more we are willing, like Christ, to submit our will to the will of our Father, the more plainly he will manifest his will to us. And this mostly happens through the Holy Ghost. The more we obey, the more clearly we can hear it.
But it all starts with that first determination to repent and keep the commandments.