I think Justme found that timing on nursing the calf before showing is a big factor. she'll also tell you to make sure no one trys to milk out the cow's udder the night before show.
Start early with the calf. Let momma know you won't hurt the baby and get the calf to work with you well. Nothing worse than an Angus momma thinking you are harming her calf. Trust me... It doesn't end well for either one of you!