I get confused and I am just learning like you. There is a ton of material on the "Net" to explain it, and it still is not easy. BTW the days of the week and the months always take the article, but you don't translate it.
The differences between por and para takes a very long time to perfect. Learn some typical patterns and add to them little by little. In most cases, even if you make mistakes, you will be understood. Work to perfect your usage, but don't let it drive you crazy.