just ceep tring just bring 10 potions and lelvel up your pokemon to level 15 19 it took me 4 trys to beat her be carfull about milktank its level 18

Read more: http://wiki.answers.com/Q/How_do_you_beat_the_third_gym_badge_black#ixzz1TYa1R6pT

How do you beat the second gym in pokemon white? well the gym leader is a normal type pokemon user so use a fighting type and level it up enough and you have an advantidge.
if you started with tepig, try to evolve it to pignite. go to grass farthest to the left where 2 pokemons may come out. there should be timburr and throh. try to catch them around level 17. watchhog was difficult because of "retailiate" which doubles in power after the 1st pokemon is killed

black/white

Once you get to the first gym you may notice the gym has three leaders instead of one and is all ways your weakness no matter who you chose. It get annoying i know but thats how it is.