Yay Leo! Here have a forum ball :).
Your goal next season should be to avoid relegation and expand the arena. Trust me, Division IV is a place you don't want to be (most D4's are inactive and therefore no fun at all, and it's hard to save up money in an active D4 compared to D3). Not only will it be good for your finances to remain in Division III, it'll also make the game more fun as you'll be competing against active teams instead of a bot league that you'd be likely to fall into should you relegate.
On the other hand though, tanking next season does have it's benefits if you can accept the idea of next season and probably the season after that being boring for you. For starters, you can take full advantage of not having to pay the salary floor for the first 16 weeks and gain some big $$$, though it might not be as much $$$ as you'd be hoping for because eventually the fans will get sick of supporting a losing team.
The 2nd reason to tank would be to gain the 1st overall pick in your league draft. This would almost guarantee you a great player (well, potentially great, you still have to train them) as long as the draft isn't a poor one and you pump a lot of points into it. But again I must stress the fact that this is the boring option and the more exciting option for you is to try to avoid relegation (and who knows, you might still pick up a great draftee with that mid-round pick).
You have an 18yo star potential player so if you're going to train anyone in your initial squad, train him, but don't invest too much money, if any, into training staff until/unless you pick up someone better in the draft or on the transfer list. Out of the remaining players, I suggest cutting your 6 worst players for now and keeping only the best 12 on the roster. If you want any help in determining who your worst 6 are, take a screenshot of your skills table in the 'set your lineup!' page and share it (you can BB-Mail me if you don't want the general public to know your player skills, though at this stage that's probably the least of your worries).
Here's a user-made FAQ that you'll probably want to read as much of as you can:
(144856.1). Some of the advice is outdated (like the tactical advice and the draftee wage estimations), but most of it still holds up very well today.
Last edited by Jay (OTT) at 2/15/2013 11:58:32 PM