Look at the custom settings as etherial mentioned. Adjust to AF priority biased and not drive, also check that you have 2.5m focus limiter enabled. There are other bits of settings to muck around... you'll soon find one that suits you best... but not before loads of missed shots.

I used to take my dog (JRT) running towards me and stuff and using the same method.. too me a while to get the settings right.. but got there eventually.

Enjoy shooting!