I always start by doing scales and also runs of arpeggios.
Then I pick something (sometimes randomly) out of either Salzedo’s Conditioning Exercises book or Friou’s Harp Exercises for Agility and Speed.
I then will often just play some simple early recital pieces that focus on different techniques or skills. Typically I like to use Imaginations by Doris Davidson.
And last I will sometimes flip open a fake book and play something randomly just to practice my sight reading and ability to form chords on the fly.