힘내 (him-nae) = cheer up! 다 잘 될 거야 (da jal dwel keo ya) = everything's going to be okay :) 걱정마 (geok jeong ma) = don't worry 당신은 할 수 있어 (dang shin eun hal soo isseo) = you can do it!

I usually use 아자 아자 화이팅 (aja aja hwaiting) to my friends who are Korean, it kinda means "Go for It!/Good luck!/Cheer up!"

"keep your spirit up!" = 기운내! You are right. Hwaiting (파이팅) is the English word "fighting". We shout this when we cheer somebody or our favorite team in a sport games or enhance the mood at a party. Some Koreans point out that it is Konglish (broken English) and it should be "go for it". But, in fact, Hwaiting became a too popular slogan in Korean society no matter whether it originated from English and so I don't think there will come up a substitute for hwaiting in the near future.

AJA! :)

haha...right on the head.