Tonight's evening prayer had those wonderful verses from Romans 8, worth quoting in full, Likewise the Spirit helps us in our weakness; for we do not know how to pray as we ought, but the Spirit Himself intercedes for us with sighs too deep for words. And He who searches the hearts of men knows what is the mind of the Spirit, because the Spirit intercedes for the saints according to the will of God.
What a relief! If only I remembered this more often when I'm wondering whether I'm even asking for the right thing: should I pray for my son to stop dating a non-Catholic when he might, after all, be the means of her conversion? Do I pray for this terminally ill elderly person to be cured, or for his happy death? And then there's days that I know there are people who have asked me to pray for them but I can't remember who it was or what they wanted prayers for. Or at those times I'm so overcome with worry or sadness or fear or anger that I can barely formulate a coherent thought about anything, much less a prayer.
All I really have to do in these situations is to say, "Holy Spirit, you know how and what I should be praying. Please sort this out and pray in me according the will of God."
I'm not sure which of the 7 gifts this falls under. Maybe it is something separate. But it seems to me to be the greatest of all the gifts that the Holy Spirit gives.