I feel the best results late afternoon/evening/night (but that could also be because I'm a morning person and I'm always really energized and caffeinated in the mornings, and more receptive later in the day).
I ground with a metal spoon attached to copper lamp cord to a copper rod at the other end, which you place in wet ground while placing the spoon bowl somewhere on the body (wherever hurts, or a acupuncture meridian point). Works well, faster than just being barefoot or sitting on the ground, works well in conjunction with these. I even have a spoon in place when i sleep, running through a trapdoor into the earth floor of the basement (out a window would work too).
I've also been practicing Wim Hoff method, running in shorts and t-shirt barefoot in the cold, at the end of which I lay down in the snow for two minutes. It feels like it's helping my immunity and recovery time, and is more grounding with the cold aspect of it. Not sure if this is practical where you live.
I have also noticed that the earth's magnetic field is doing some really weird stuff lately- feels really strong- a lot like an EMF field, but good- and this seems strongest in late afternoon to me, and in sunlight on clear days with blue sky- I notice that I feel really energized (spring fever type energized, where it's hard to sit still), and hungry afterward. I wish there was a way to measure Earth's magnetic fluxuations. I feel like grounding during this, whenever we can find it, could have incredible healing results.