What a blast from the past this is!! I'm going through and re-exploring subeta and seeing the website layout has me all nostalgic.

As a returner, does anyone have advice on where to start :3

First, welcome back! Second, you should wander on over to your Dashboard because you may have some age-related achievements with loyalty boxes waiting for you. That's probably the best place to start. Second place sort of depends on if you are a pet person, clothing person, etc, but doing daily quests probably won't hurt to help build up some cash (at least on the legacy site. If you are on kumos, sometimes there is inflation limiting the good of quests)

I am trying to return as well!!!!

Oh wow, welcome back! I think you should do some daily quests (like Gossamer said) and to focus mainly on the Wizard (for Wizard Tokens) and then Saggitarius, because his rewards give more much more sP. I don't remember what year they did that change, but they made it much more easy to search for the item in the User's Market so it's less of a hustle. At the same time you can open a shop, put there all the mundane/simple items you get and update the prices once every few days. Profit piles up pretty fast during the month. it depends on how often you update the prices. Honestly? I would subscribe for a CSC plan. I don't know how is the currency from where you are, but for me it's fine. You get CSC and a special item (that you can sell in the shop if you don't like) each month, and start getting some Costume Items that users make.

Other than money and clothes, you can start working on pet profiles. You can make a pet with the theme of a character you like, your own character, of a real pet you have or even a just a concept, like a season or something (you can check my pets if you wanna see what I mean). I like collecting the items of the theme you choose (they are being displayed in the pet profile) and building the whole thing. You can also add background and design the pet profile look, it depends on how much you are willing to learn to do that, or pay someone else to do that for you. :)

I never got into the battles so I can't give any tips for that. Ofc there are also the forums for chatting and some nice classic flash games. Events usually happen on holidays (Halloween, X-mas and etc), and we are hoping they will bring back random events with a story line (there was a poll recently ,asking about things users wish to see more).