If there's just one piece of information I would give to anyone out there who cares to listen...it would be "to persevere."
Perseverance is the key to success. I know there are times when you wonder at what point should you quit, but if what you're doing isn't working, find another way of doing it.
If it's your dream, or your passion, never give up. If you don't have the knowledge, learn it. If you don't have the time, work out how you can make time. If you don't have the money, take on an extra shift at work.
If you really want it...really, really want it - do whatever it takes (as long as it's legal) and persevere until you get it!