Phase 2 has just been announced, and is coming in a month! So let’s take a look at what I would focus on for the last period of Phase 1.
Get your alts ready
The most important thing in my opinion is to make sure you have access to all the professions. Having professions available is the easiest way to make sure you can pivot to the right recipes and craft the top sellers of any given phase. My goal is to get three characters to level 25, so I can cover every crafting profession that can sell on the Auction House. I can then quickly get them to 26 to access 225, and then gradually level them to 40 over the next phase for access to max level professions down the line.
If you want to try-hard you can prepare your profession alts with enough quests ready to turn in to immediately reach level 26 as soon as phase 2 begins. You are then ready to level your professions to max. You can also pre-buy a decent chunk of the materials required to level, as a lot of the recipes used for leveling use materials that are currently available.
With the announcement of phase 2 I expect some items will have spiked a bit in price already. I will not give specific item suggestions, because if everyone piles in to the same item, it will go badly. In stead focus on checking the reagent list for crafts that might be relevant in the next phase. You can use the search feature on wowhead to look for items, as you can see in the screenshot below I’m looking up relevant elixirs for the next phase and the required materials. If any are farmable now they are prime candidates to go up in value.
I’ve mentioned some other examples of currently available recipes that remain relevant for all of classic, and they are of course also good options for investing (thistle tea and free action potions in particular come to mind).