Due to a change in circumstances I now have a different layout to my mornings, and as a result I have embarked on a re-reading of Nisargadatta Maharaj's book 'I Am That', which you can download freely as a pdf from the internet.
One of the things he said is that a longing for enlightenment and an earnestness are the most important elements in the search, that if you have these they will take you swiftly towards your goal. That any form of practice was just form for this longing, and that even without practice sitting and focussing on the longing itself would ensure your progress. But also that if you practice without this longing, then the practice would not help.
I found this insightful and also that it fits with Buddhist practice, where the bodhicitta is also meant to take one towards enlightenment. That longing is one of the very last desires to give up. The other thing that I liked about this chapter from 'I Am That' was that he said that the very idea of enlightenment was like a seed planted in the spirit, which would eventually come to fruition.
So a very useful pointer, to keep the longing for enlightenment in your mind, and not to focus too much on the practice.