Clean everything to the point you would not have any trouble eating off it.
Check for any damage, scoring and such on the spindles, and were the inner bearing race contacts the spindle.
(figuring you are using new bearings and races and reaces ar properly pressed)
I put a glop of grease on a flat piece of waxed/butcher/parchment paper and "swirl" the bearing in small circles in the grease (cone/base down, small side up) until grease is coming up throgh the top, or glop on palm, and start "digging" the base in the grease in the palm until it is coming through the top, rotate and continue until the entire bearing is filled. and then install the rear bearing, then the seal in the drum/hub, set the drum/hub in the sppindle.
Then do the same for the outer bearing, and install it, then the retaining washer, put the spindle nut on and torque to 25 ft lbs to seat bearings, then back off nut and tighten by hand until you get to the point that you can get the cotter pin in.
You do not want any more pressure against the bearings than the absoulute minimum of torquque.
If you over torque, even by a small amount, the deformation of the bearing cage and the pressure pushing the rollers aganst the race will result in rapid wear, scoaring or galling of bearings and race. The intent is that the bearings ride on the race, with a light film of grease between the surfaces. Too tight and it is metal against metal, which is not the intended engineering.
It is easier to over torque than under torque wheel bearings. (learned from aviation maintenance and near 200 hundred MPH and more than 100,000 pounds of weight in wheels....)
And I love "Red and Tacky" for wheel bearings as it ensures a good supply of grease is always in contact with surfaces. That stuff is persistant as all get out.
Hope that helps. :)