Earning gold in World of Warcraft: Classic is all about optimizing your spendings. Back in the day, your character’s skills were acquired from a trainer, using money. Don’t just buy everything he or she offers! Read the skill descriptions and be mindful about them. Quite a few characters can live through the levelling process without learning some of their utility or damage spells. These won’t go anywhere and you’ll be able to learn them later on.
You can’t go wrong with a mage. In fact, Mage was the most popular class in World of Warcraft: Classic due to their ability to farm with ease. Back in the day, the player majority even leveled mages as alts in order to gather gold quickly. In addition to their monstrous ranged DPS, mages also have tons of useful utility. As a mage, you’ll be able to conjure food and water, place portals to the major cities, and even earn gold from doing so.
The leveling guides on my site are essentially speed leveling guides. My leveling guides are the same guides I use myself to speedrun to 60 on new servers to get 60 server first. I list many occasions where I tell the player to "die on purpose" to go faster. I tell the player to skip certain quests, because some quests are just not worth the time/XP. I list tricks and shortcuts to go faster so you can reach level 60 much quicker. I am still constantly going through them over and over again perfecting the guides to make them faster and easier to follow. For the most part, the guide can be followed without the need from other player's help, as the whole guide was made from a solo run anyways. Although I do list quests that can optionally be done if you have a group.
Unlocking the Lightforged will require you to complete the aforementioned Argus storylines and earn the “You Are Now Prepared” achievement. In addition, you’ll have to earn Exalted status with the Army of Light. As with the Argussian Reach, this one could take a couple of weeks, as it is time-gated. However, the main story quests should help you at least reach Friendly status with the Army of Light.