Look for all of your classical "cow things" like structure, balance, muscle, femininity, and capacity.
Structure should be your first priority. Problems will only get worse with age and weight. Length and deapth are super important with width and thickness coming right behind them. Look at her chest floor and how wide she is at the top of her legs, this will give you an indication of actual skeletal width. Look at legs, front should be straight from the side and front view. Back should be straight from the rear and from the side have a little set to the hock. Also, look to see that she is level from hooks to pins. My ideal angus heifer is long bodied with the depth (capacity for a calf) to match. She should also be very feminine through her head and neck. If she is not then she will place below cattle that are otherwise not as good but prettier fronted. Also, look at how she moves...when walking to or away from you her feet should move in near straight lines and from thr side she should reach out with that front foot and step in (or nearly so) her front footprint with the back foot without her tailhead dropping too much.
This is a fairly basic version as i am unsure of your knowlege but if you do know what you're doing then she should grab you as soon as you see her.
Best of luck!
