If you want to level a rogue in Wrath of the Lich King it is recommend to use a guide for faster and more efficient leveling. Some new guides are available as addons for the game, so you don't have to switch between a website, a book or something else and the game.

A good guide takes you to both start zones so you can benefit from the gold rewards and experience in early levels. When your character turns level 80 the quests become 'grey' and give less gold and experience rewards. The quest-XP in higher zones differs very little from lower zones. You don't have any advantages going to higher zones early. Quite the opposite is true: Questing in lower zones is faster than in higher ones and therefore you gain more experience. That way you can easely hit level 79 to 80 in 3-4 hours.

It is recommend to start in Borean Tundra as horde and in Howling Fjord as alliance. Once you completed one of them start questing in the other one. After that you start questing in Dragon Blight.

So it is guaranteed that you took all quests from the two start zones and have every follow up quest in Dragon Blight. When this zone is done go to Grizzly Hills, then Zul Drak. In most cases you reach level 80 there. So three zones are entirely free to harvest money from if you clear them with level 80.