Many people are very inefficient when it comes to earning their gold. The key to making tons of money is using time wisely; always be doing something that helps you in the best way possible.
Example for clarity: The most gold/hour for my rogue is farming mana tombs chests which has already been posted (grr). However, being full epicced I do all 5 runs in 30 minutes or less depending on spawn location. This leaves around 30 mins of free time each hour, so I planned out my day to be more efficient.
Step 1) Farm 5 mana tombs
Step 2) Do 2 netherwing quests (Usually mine first as it is less crowded when I start earlier in the day, I always do cargo and either skinning or ravager kills, whichever comes first. Make sure to always pick up the ravager quest so taht even if you do not finish it now you should have 1-2 kills at least saved up for later)
Step 3) Hearth back and complete 5 more mana tombs.
Step 4) Do bombing in skettis (on my high pop server escort is almost never worth 9g and low-rank pots) then fly to BEM and finish as many as you can do in 30 minutes, I can do all 4 so it works out nicely.
Step 5) Hearth back and complete 5 more mana tombs.
Step 6) If I am inspired to do NW I will booterang and finish the currently unfinished mine quest. Or I farm netherweb spider silk right to the east. Or I farm cobra scales in nagrand (less traffic then in SMV). Basically this is your free time now that most dailies are done. If the pvp daily is anything but EotS I've found it worth it to get a quick group from your guild and blast through a bg, usually never taking more than 25 minutes.
Note: If I ever finish dailies with time to spare I find something to do nearby, such as stocking up leather to complete that NW daily easier tomorrow, or taking a quick trip to Stonebreaker Hold to mail all my newly farmed gems/greens/scrolls to my bank alt.