1. You look for stocks that are selling for less than their Fair Value. Think of Fair Value of representing what the stock should sell for if it was neither overpriced nor underpriced. I capitalized Fair Value because it's an actual number determined by a rather rigourous financial analysis and mathematical process. However, if you can't do it yourself, you can subscribe to a service that calculates it for you. Morningstar is what I subscribe to. But basically it's buying something for less than it's worth, because the general public hasn't yet discovered its worth. eg your Colt SAA.
2. Nobody*. Market price is the price. Though there is a spread between what the buyer pays and what the seller gets, usually fractions of a cent to a couple cents, and the broker gets a slice of that spread, the exchange gets a slice of that spread, and any other intermediary gets a slice. Market price is determined by supply and demand. More buyers than sellers and the price goes up, and visa versa.
3. See #2.
4. You wait until the general public recognizes its Fair Value. Or until the company reports earnings and profits much better than expected, and the general public wants to buy, making it a "hot" stock. But that's trading and not investing. Nothing wrong with trading, but most people lose money doing it, because they're victims of the same psychology that makes the general public chase something that's "hot". eg Gunbroker, hah!
5. Basically you do nothing to "improve" the value of a single stock. If it's a stock of a successful company, it will increase over time as their business grows and along with that your little "piece" of ownership represented by your stock. Increase is not straight-line. There are ups and downs. So you hold a portfolio of the stocks of great companies and their individual variations to some degree balance out. Warren Buffet's holding period is "forever". Never sell. That's investing. The objective is to improve the overall value of what you own: ie your net worth.
* There are exceptions for certain types of financial instruments that enable buying or selling at a pre-determined price, but you pay for the privilege.
... end of off-topic (hopefully) ...