Don't ever give up. Don't ever give in. Don't ever stop trying. Don't ever sell out. And if you find yourself succumbing to one of the above for a brief moment, pick yourself up, brush yourself off, whisper a prayer, and start where you left off. But never, ever, ever give up.
Never give up. It's like breathing—once you quit, your flame dies letting total darkness extinguish every last gasp of hope. You can't do that. You must continue taking in even the shallowest of breaths, continue putting forth even the smallest of efforts to sustain your dreams. Don't ever, ever, ever give up.
If the fire in your heart is strong enough, it will burn away any obstacles that come your way.