I initially look for a powder in the manual that will fill the case to the bottom of the neck and provide the highest velocity. I don't like a lot of space between my powder and the bullet.
At the range I run a couple rounds downrange to foul the barrel. Then I have an average 4 different loads of 6 rounds each. After the fouling shots I let the barrel cool.
I take 3 shots from each load allowing the barrel to cool for at least 2-3 mins before each shot. After the 3rd shot I wait 10 mins. (marking the target during this period make the time go faster). I repeat this for all 4 loads. Then start all over with another string of 3 shot groups.
If I find a particular load that groups the best I then load up more of it with various seating depths from just touching the rifling to off .075"". This of course is magazine permitting.
Just a note, I've loaded so many different cartridges/calibers that I would have to actually sit down and think about it. But as I recall I only ever had one rifle, a 30-06, that liked a load that was listed as maximum. Actually a bit more with no pressure signs.