You can check and check and check some more. It never seems to make much of a difference.
Sell a group to a buyer and think you did okay. Take the rejects to the sale barn and do better. Go figure.
You can only hope there are two or more people looking for what you got when they go through the ring.
In '08 I bought 20 additional lightweight heifers when prices were upside down. Corn wrecked the market as we knew it. To bad I didn't buy 100. I made money on every single calf I bought and that doesn't happen often. It must have rained that winter :-)
People have told me, "You could have bought that one for X dollars?" when they come through the ring. That's never true. The person who took than animal might have been willing to pay more and all I would have done is run the price up.