As kalista, Her mobility is everything in her kit. Make sure you go for short burst trades and then get out before she can get too many spears in you.

Work with your Support to kill her. The best time to all-in her is when her r is down, or she is CC'd.

Post-six, you will want to be careful about her Ultimate. Failing to do so will easily get you knocked up and killed.

Keep the wave near your tower and see if you can expose her to ganks. As kalista, Its mobility is everything in its kit. Make sure you go for short exchanges and then exit before it can get too many spears in you. Work with your support to kill it. The best time for everything in it is when its r is down, or it is CC'd. After six, you will want to be careful on its Ultimate. Do not do it will easily make you bury and kill. Keep the wave near your turn and see if you can expose it to the ganks.