In 1 Tim. 4:8, Paul wrote, "For while bodily training is of some value, godliness is of value in every way, as it holds promise for the present life and also for the life to come." In this text, the parallel between "bodily training" and "godliness" is instructive.
In physical exercise, we train our muscles to be strong and agile by a regimen that regularly forces them to do things that are hard to do. Over time, our muscles develop the ability to do harder and harder things -- but only by having been called upon to do things that were very hard in the first place.
Similarly, we won't grow unless we continually call upon our spiritual "muscles" to do things they find hard. With that in mind, ask yourself:
(1) What am I disciplining myself to do that is hard for me to do? As you ask this question, keep in mind that what is hard for someone else may be easy for you. We are looking for things that you personally find it hard to do. "No pain, no gain," as the weightlifters say.
(2) How regularly am I requiring myself to do these things? Down through the centuries, many have found it helpful to have some daily regimen of spiritual discipline. "Once in a while" won't get the job done. The athlete who finds himself saying, "I'm too busy to train today; it won't hurt to miss just one day," is probably not someone you'd expect to win a future gold medal in the Olympics.
For example, think about something like a daily Bible reading program. Many would say, "But I can't read the Bible every single day. There are some days when it is just so hard to get my reading done." Well, yes, it is hard -- and therein lies the value of it, at least from the standpoint of spiritual training. The very act of doing that which is hard is beneficial, not to mention all the other benefits of the reading itself.
The willingness to pay the price and do the hard things is what separates those who really want to go to heaven from those who simply think of it as a nice idea. So honestly, how much does it really mean to you? Are you willing to train for it?