I am sure that you already know that the more you earn it's also the more you spend and it's very important not to spend more than you are earning because you will be a defaulter because am sure with such stand he or she can not pay back his or her depts.
However, one must learn to cut their costs according to their size. Which means if you want to want to begin investment and saving and keeping a standard of life, you should also earn more. But if you are earning lower, you should maintain a certain standards do that you can meet up.
One should live below their means, otherwise, you will have financial trouble later on. Much better to take care of your financials before anything else, luxury or other needs, because you will be the one suffering from its repercussions later on.
As much as possible, save something even if it is in small increments of savings. Savings will give you peace of mind that in case of trouble, you have something to rely on. Whereas, with investments, though you have no assurance that you will profit from it but at least you have the chance to grow your money. So you also need to weigh your chances here and assess your investments. If you are not making money at all, better find alternative investments to explore with.