Tanquerey gives some wise advice. He says that
We must [...] strive seriously to repel promptly the distractions that present themselves to our mind;He also says:
We must, likewise reduce the number of such distractions by a vigorous fight against their causes: habitual dissipation of mind, the habit of day-dreaming, the preoccupations and attachments that absorb the mind and the heart."It is important to bear these things in mind first because such faults are easy to fall into and very common. Channel-hopping through useless things on television, or surfing idly and without purpose on the internet are examples of what he means by "dissipation." However, once we have seriously tried to take the steps that he recommends, he says,
[...] there is no cause for worry concerning such involuntary distractions as run through our minds or disturb our imagination. These are but trials, not faults, and once we have learned to profit by them, they but increase our merit and the value of our prayers.The principal means of "profiting" from such distractions is to understand them as a cross and to embrace the cross humbly in union with Our Lord, recognising our unworthiness to be speaking to him, and thanking him for purifying us in this way.
I think that also we can offer the time that we give in our prayers as a sacrifice. It is of the nature of the holocaust sacrifice of the scriptures. We take some time that is ours: we can spend it in various ways. Rather than waste it on something useless ("dissipation") we make it over to God without reserve. It becomes His time to do with as he pleases. We may then be sure that he will act in our soul in the way that He sees fit, to draw us closer to Him. This will be true even if our prayers do not seem to us to be very devout - sometimes even because we do not feel very pious. "Our Lord does not ask us to be successful, he asks us to be faithful."