Also, when I was an assistant editor, we all agreed that the best directors had started out as editors. When you are shooting, always keep an edited scene running in your mind; think about what cutaways will be good for what a person is saying; when you are shooting action, figure out how you are going to get CUs of the same action, and move fast. the alternate angles might not happen til another day, so you have to keep them in your mind. It's so mesmerizing to get caught up in the continuity of what is happening, but you have to really think fast about how much of any given activity will end up in the final product.
Almost anything can be 'fixed in post', as long as you have the right cutaways!
(Last year I cut an amateur shooter's film about a relief kitchen in NO, and there were NO (zero) shots of people actually using the facilitiesâ€¦huh? We shot this after lunch, I was toldâ€¦And you didn't go back the next day??? (Still photos actually saved the day, in this case)