BLUPing.

Here are some tips when BLUPing.

Are you going to fully train, or only train for necessity?
In order to BLUP correctly, you must bold the top three skills, so in theory you can just train in the top three skills. However I prefer to train in all skills, this gives a 'better' resale value and enables a horse to excell in all disciplines.

Competitions first. 
What I mean by this, is that you should train only the top three skills first. 
For example, a horse that excells in Dressage.
Train 75% or there abouts in dressage
train 50 % in the next best skill
and 10% or 0 in the final best skill.
This allows the horse to qualify for lower ranked and lower difficulty events, and will give you a better chance of winning them as opposed to being up against the best of the best. 
 After you win 20 competitions, you are free to train just the three best skills or all the skills, do lessons and rides and get that BLUP of +100.