Some of the things that I live by and have helped me are:
The answer is no 100% of the time you don't ask.
I wouldn't have an EPIC right now. I wouldn't be in Dubai right now. The list can go on if I didn't ask some pretty crazy questions knowing that the least would happen to me is be told "No".
Don't be afraid of failure.
More times than not, it seems when I try some something new, success comes. When failure happens, I still learn new ways to not do something (learning what is "wrong" almost always teaches you how to get closer to "right"). "Trying" is a win-win situation.Strive to surround yourself with the best...and if possible, try to emulate what the successful people are doing
Hanging out with only people on your level will not push yourself very quickly to a higher excellence which we should all be working towards. Growing up, I have not been the best person at explaining stuff out loud to people...but it's something I like and want to do more. What I have done to get over this is by listening intently to how people like Ted Schilowitz make their speeches. Observing what the best do can only make you better. I have been very fortunate to become great friends with a lot of the RED Team, and this I believe has a lot to do with why I am where I am now.
Perhaps the advice above is not necessarily the best advice for "cinematography" per se, but it has definitely shaped who I am as a person and has directly influenced my little bit of success in everything (including cinematography).