As some people here mention, please don't spend all the money on expensive machinery or new machinery, you can wait for sales, don't sell all the grain as soon as you harvest it, unless there is a great demand for that grain you are harvesting, you can get a good price from selling it when the price is high (you can check the prices tab) or invest it in production chains and earn good money for that, also, contracts are a great way to get some extra cash as well! The choice is yours!