if you do BG's some brackets, you'd benefit training as often as possible while other brackets you can hold off 2 or 3 rounds of training. Depends on the class and level bracket your at. I've found on the average training at 10, 20, 30, 40, 50, 60, 70 and 80 are pretty much required. in between each 10 levels, i refer to the begining of my post. Its a preference as at some levels the your new ability is pointless (such as lock when you get Curse of Weakness upgrade when you use Curse of Agony all the time). Usually between the Every 10 required training, I train 1 or 2 times depending how hard the BG's in that bracket level have been for my toon.
As for gear, once in awhile buying BG gear is nice at low level as its cheaper then AH (easier if your starting new on a realm and low gold is a issue). the autoequip addon is a must for those doing leveling and/or leveling/bg mix. makes life alot easier not having to worry about buying gear. Again, a good practice I've found is at the 10 level training break, check for gear that might be over 10lvls below your current level and check the AH for something better (and cheap). If you want check for gear for the next level range also and if you are able to buy it get it and place it in your bags. so that once you hit that level and you have the autoequip enabled it will auto matically equip the new gear. It does change per person and play style (class and talent tree also) though so keep that in mind.
oh also, consider heirlooms most def. a 5 piece set is great to have (chest/shoulder 10%x2 boost to exp and honor is a godsend) not to mention the boost in stats from all 5 times as you level is almost impossible to get at those levels from anything other the epic (which doesn't usually get as high also). The trinkets at low levels that are best are the boost in mana and boost in health after every kill.
So far i average getting from lvl 1 to lvl 60 in roughly 4 days play time doing a mix of leveling and bg's using the above rules. After lvl 60 i usually handle things a little differently and start considering respecing my toons.