I've always though that the AE-L button was wasted space on almost any camera!
(the exception being that they should be compulsory on Auto only cameras!).
If you want AE-L for any given situation, simply switch to manual mode! Alternatively learn how to use
exposure compensation.
All AE-L/AF-L buttons should be annihilated, cremated, and their ashes spread across this land, far and wide(with an ensuing dance of celebration to mark the passing of a pretty useless function button).
AF-On on the other hand ... should be made compulsory! No camera should leave the factory floor without one, or it being set to Off.
If I had my way, people wouldn't be allowed to purchase a higher end camera without first knowing how to use the AF-On button correctly either!
(I'd have them all purchasing and using P&S cameras, or smart phones)
OK, the serious answer now: set it to AF-On, practice it's usefulness and grow from there. Also, remember to stick to a single AF point that you determine is the best one to use.