A true brangus does not have much hair. I would keep her clean. Wash her regularly. Clip her head back to her ears about 10 days before the show. Since this is the first time for her to show work with the calf a great deal, handle her easy, brush her daily after she is broke to lead, find out all the shots you need to give her to take her down the road and get them early (many require a second shot), before you show her take her in the trailer to other places and practice (even a neighbor's barn or another lot), use a radio in her stall to get her use to different noises, have other animals run around her, and something we did ever year was to tie them beside a main highway (inside our fences of course) to help her get used to changes and noises. We never had a problem come show time. Brangus sometimes are heady....I will snychonize 50 head tomorrow...we culled out 40 or so last week and put in CIDRs and gave their first shot. Maines are puppies.... we never showed a brangus ourselves but we did Limmys, Semmys, Chi-Angus and the Chi-Angus can be tough and my guess is some of the Brangus will be the same way.
Hope this helps... Best wishes.... Brangus heifers are very beautiful....