I insisted that all learn to swim the 100 with a maximum of 2 seconds difference between 1st and 2nd 50. Our best swims came when the difference was 1.5 sec or less. We practiced sense of pace relentlessly.
Now if I could do that I would make a huge improvement in my 100m time.
Would the best approach be to swim slightly slower for the first 50m or 75m and then try to accelerate or just continue to work on aerobic fitness so that I die less on the last 25?