okey..first of all i have to say sorry for my english, but i think you will understand it.

Shyvana is a strong Champ who makes dmg with her skills.
So it is important that you will use this information.
Thats why i use Greater Glyph of Celerity in blue for low cooldowns.
Her passive allows her to low the cooldown of her Q with her auto-attack.
Thats why i use Greater seal of alacrity in yellow.
And to do the max. dmg on minions and champions i use greater Mark of Desolation.
Moreover to stay long on youre line i prefer to use Greater Quintessence of Fortitude.

Pros :
easy to farm
strong in team fights/ and solo foghts
dps king and tanky

cons:
easy to gank befor she is lvl 6

when you play and 1v1 fight..try to hit your enemie with your E first then use your R and W
after this you can spam your Q and E since he is dead.
do the same in team fights^^
think of it..you can fly for a second..try to come near to the carry ad or the ap nuke..you are tanky enough to surrive it and get the kills.