If you have acidic soil, now is a good time to add lime. Or if you have acidic soil and deficits of phosphate and potash, you could add wood ash.
If you wanted to warm up the soil, now is a good time to put out plastic mulch. But it sounds like you don't have to worry about warming up the soil.
My winters are more severe (in a normal winter I'd have snow on the ground until 1-4 weeks past the official start of spring), but about four weeks before planting is when I would add manure. I use horse manure because I have a large supply handy, but you could use whatever you have available nearby (e.g. if there are sheep, dairy, or horse farms anywhere near you). Unfortunately I can't say how much you should add, because I don't know how fertile your soil is. I have beds that I didn't add any manure to this year, but others (especially where the corn and squash are growing) got a whole bunch.
I wouldn't bother watering if you don't have anything planted, this seems like a waste of water.
This is about the time that I would fork my beds for aeration -- I generally don't turn them over, just move the fork back and forth to loosen the soil a bit.
This is also the time that I'd plant early crops: spinach, spring onions, peas, oat cover crop, etc. (I also would be starting stuff inside now, but you didn't ask about that.)
About 3 weeks before planting is when I would till cover crops like winter rye, and then repeat a week later. (Crops that are easier to kill I'd only till once, but winter rye is pretty vigorous.)
