I don't have a precise method either; I freely mix some techniques I've tested in the years that include stabilizing and analytical meditations, pranayamas and mantras, but like you I always start by letting my thoughts flow around, I just watch them and let them fade to keep the sense of the "now" moment; then I usually do a "body scan" to set my physical presence in the world; finally, I go on with the formal meditation.
For me the early morning (~5:30) and the late evening (~23:30) are the best moments, with 20-45 minutes sessions. The half lotus position works well for me.
"How to Meditate" by Kathleen McDonald is a excellent and exhaustive manual about the practice.
Have a nice day! It's time to sleep for me :D