You can increase the effectiveness of your character by a large power leveling amount with inscriptions! Many inscriptions were designed by blizzard for certain purposes so you will have your options of major glyphs which are suited for PVP, Raiding and Leveling! check the class forums to see what they are considering the best inscriptions for lowering downtime and raising dps.

A lot of consumables have dropped in price considerably since the market for raids has been wiped out, you can buy flasks now that last for 2 hours, last through death and increase your dps by a large amount, these are a great investment if you can find them for a reasonable price if you aren¡¯t too strapped for cash.

My favourite is buying the flask of undeath to give my frost mage. A good boost in dps, that¡¯s +80spell dmg for 2 hours for about 20g.

Mana/Health pots are always a great idea to have on hand for tricky situations, they can give you a bit of help on that tough quest you are doing solo, and can save your skin from a death which would really lower your exp/hour

Stay away from battle/guardian elixirs, which go away on death, as there is a power leveling high chance if a mob doesn¡¯t get you, you may get ganked if you are on a pvp server and will make you that much more frustrated.