This is quite a broad general question, but this confuses me too. It is not like that 1830-obvious in a sense you do not start a company with lowest possible price IPO and then move with a 100-IPO. I know there are strategy that works but that least the above cookie-cutter will keep you in game most of the time.
What is the general strategy of this game? It is a bit confusing as it is a 18xx but with not enough companies for players to move stuff around, intentionally designed that way. So how should we start? What is the big picture strategy to 'not lose so bad' at least?
Its a route building game. So the goal is to see what would be a good route on the board and make that happen over the long hall of the game. Generally I think the winner has one of the best routes from a token in Chicago to the east side of the board. You need to see what companies and privates will work best together to make that happen. I have also found that withholding is not as bad in the linear stock market games. If you can without a time or two but then get a train that will give you a couple jumps in the next two OR's than you are still coming out ahead. I am by now means and expert but those basic ideas have worked pretty OK for me in games that are more about good route's than stock shenanigans.