In The Hunger Games, in what ways is Katniss prepared to be a contestant in the Hunger Games?

Katniss is prepared for the games because she knows how to use a bow and arrow and she has good survival instincts.

Even before the Hunger Games, Katniss is tough.  She is probably the one person from her district who had a chance of winning.  Her skill with a bow and arrow is very useful, but more importantly she is independent, strong-willed, and a fighter.

Katniss desires to survive.  She has never had much, so...

Katniss is prepared for the games because she knows how to use a bow and arrow and she has good survival instincts.

Even before the Hunger Games, Katniss is tough.  She is probably the one person from her district who had a chance of winning.  Her skill with a bow and arrow is very useful, but more importantly she is independent, strong-willed, and a fighter.

Katniss desires to survive.  She has never had much, so surviving is what she has done all her life.  She would illegally hunt in the forests outside of her village to feed her family.  Her skill with a bow and arrow ensured that she could catch food, but it also gave her an edge in the games.

Independence is an important trait for survival in the games.  Katniss does not need to rely on anyone but herself.  She is quick-witted and learns fast.  This helps her evade or defeat her enemies and understand how the games work.

Katniss’s empathy also helps her, ironically.  She may not love Peeta, but she cares about him and wants him to survive.  She plays along with his star-crossed lovers act in order to win sponsorship and support, and it gives Haymitch something to use to get them valuable supplies.

How does this affect the betting odds? Will we lose sponsors? Do we even have sponsors? Yes, I feel certain we do, or did. (Ch. 12)

If Katniss had not been daring enough to risk the double suicide with the berries, either she or Peeta would have died.  This act prevented her from having to fight to the death, but it also marked her as a revolutionary.  By surviving as an underdog and defying the Capital, Katniss made herself a symbol of hope to everyone in Panem, whether she meant to do it or not.