I did this long long ago and i still do it, (Dont flame at me if this is a repost just dont rep if it is... but i looked all over and saw nothing same as this)
Anyway here it is... i've always done this with my warrior and rogue, dont know about other classes might work too
1. Get ur weapon u wana skill up with
2. Get as much intellect gear and intellect buffs as u can
3. Go Smack some mobs and see ur skill goes up pretty fast, like 4x faster than normal
Again dont flame if its a repost, good luck