As of this writing I only have a few games in each of them, so I don’t have enough info on how to win; but I feel like I have some good advice on how to lose. I figure these are probably “more true than false” but not 100% true. As in anything, it’s situational.

1. Undervalue the special trains — The 1822 family is all about the auctions, so if you get the auctions wrong that’s a problem in any case; but the special train privates are valuable. They (usually) don’t count against the train limit, they let you pay out on your first OR. You can withhold all the other trains and pay out the special (or vice versa) to effectively withhold without taking the stock hit. Getting the SR1 “5” train private should cost …. but means you can run your first major company balls out — you’ve got a permanent coming!
2. Too few minors — Early money is always good and these are the best early money around, but …
3. Too many minors — The minors are much better “bang for the buck” than concessions, but also ticking time bombs. If you can’t absorb them in time you’ll be on the hook for a five train for each (or at least one to shuffle around, losing stock value). Instead of “Too Many Minors” you may also suffer from “One minor that’s very out of the way and you can’t link up with.”
4. Running out of cubes — Particularly at 5p, putting a cube on a private “just in case” may be a problem. Sure, some things are better than others, but seeing someone win a minimum bid (or two) because you are out of cubes hurts. (There is a secondary thought to sometimes start a bid high not only to speed up the game, but to make sure that others have an extra cube which will ensure that nothing else goes cheaply).
5. No money in SR2 — It’s not so bad if its just one person, but if multiple people spend it all in SR1, there will be bargains galore.
6. Build a great company but only get 30-40% of it — Usually the result of “too little early money.”
7. No E Train — These allow for huge end game jumps. Getting a permanent 5/6/7 by itself usually isn’t enough. The special trains allow for a non-stock killing withhold (as do mail routes, etc).
8. Timing Oopsies — Mis judging how long it will be until Ls die, or not pulling in your private companies and accidentally missing out on a certificate slot. (The major timing oopsie is the “Too many minors” having to eat an extra train).

I’m sure there are more …. perhaps I should do a roundtable on ’22, but for now just post them in the comment.