Dr. Thursday points out that we just have time to say a double Novena to the Holy Spirit if we start today.
I suggest one for the Conclave and one for the next Pope; or for the old pope and the new one; but of course, all of them would also be for all of us in the Church and for the whole world.
Any novena is a prayer said over a period of nine days, imitating the nine days between Ascension Thursday and Pentecost Sunday that the disciples dedicated to praying for the Father to send them the Holy Spirit. Novenas can be dedicated to multiple sorts of prayers or to only one, repeated every day. Anybody can make up a novena prayer, of course, but most folks go with the tried and true ones. (Of which there are hundreds.)
You can go super-simple on this if you want, and just pray a Glory Be every day, or a similar simple prayer, or just sing one of the classic hymns like “Come Holy Spirit”.
If you miss a day, don’t stop praying because of that. It’s the intent that matters.
A poem novena to the Holy Spirit, by St. Edith Stein, aka St. Teresa Benedicta of the Cross.