The most important thing that you can learn when it comes to borrowing money is that you must never borrow for things that will fall in value. This is the key that Robert Kiyosaki seems to emphasise in his books on growing your wealth.
Most people borrow money to pay for goods, which go nowhere, in that they are used and discarded.
This money goes into buying clothes, holidays, expensive restaurants, cars, or other things that depreciate or lose value. If you are going to borrow money, you need to put those loan funds into something that will generate more income than the cost of the borrowed funds. This is obviously a simplistic example, but it illustrates the point. If you are going to borrow money at all, make sure it goes into something that creates more income than the cost of those borrowed funds. To do otherwise would mean that you are running at a loss and, if continued on a larger scale, will eventually lead to ruination for you.