We all get sidetracked from our pursuit of God at times.
I think that the three main areas that cause this are distraction, discouragement and deception. How many times do we set out to pray and yet our mind is flooded with the "to do list." This is normal and so rather than thinking of ourselves as failures, we can simply change our mind to again focus on Christ.
Discouragement too is another ploy of the enemy to sidetrack us from God. It knocks on the heart of all. We only have to read the book of Psalms and realize that we are not alone in these thoughts and feelings. We can remind ourselves of the good that has occurred and that today will pass.
Deception is the last problem. I believe that it needs more thought. Too easily do we justify our wrong choices and weaknesses at times to be disobedient toward God. We need to examine ourselves. What is our true heart and who is our true god? Is it God Himself or His grace? Upon what are we most focussed?
This may sound tough but we will all have to make these choices at times. What is the best answer? To not just pray but to know the words of God that are revealed in the Bible.