You could just start trading the stock market and try to take over the big diversified companies little by little (these have the highest chance to become huge profitable companies later on - I can't remember if in Cap+ companies can change their strategy mid-game as well. Now at this point, unless maybe you're playing on very high difficulty settings, you should be a couple years in and have a profit of a couple mill/ year, that will also extend your credit line, now you can really start having fun. You should also be able to build a second and third store. It's been a long long time since I played this, but here's what I remember working pretty much all the time: Start with a department store on an urban tile, find products that have enough supply (the blue bar, (vs the red bar that denotes demand)), and a good overall rating, micromanage it just a little for a while (adjusting sales price or even changing products if demand for it is too high, if theres products with better overall ratings or if a competitor is pushing the same product at a rating (quality, price, brand) you can't compete with.

Capitalism ii guide to success