First of all, look for one that is attractive - nicely balanced, straight lines, square hip. Without a nice look, you don't have a show steer.
Watch him walk - from the side look for a long smooth stride, with the back feet setting down in the tracks from the front feet, and some flex and no popping in the hock, pasterns and knee. From the front and rear he needs to track straight and true, not swinging his legs in or out as he goes. If he wants to track wider or narrower than his body structure, pass on that one. Likewise one that turns in or out at the hocks or knees. When he moves and stops, look for all the toes to be pointing forward. Foot size and dimension of bone are important - too small won't work, but you don't necessarily have to have the biggest either. Bigger is better, just not to the point that the joints start getting coarse. If the joints look swelled or have fluid pockets, run away. Also look for the top line to stay level and square on the move.
Muscle and thickness is important, but the biggest butt doesn't necessarily win these days either. Kinda like with bone - look for all the width you can get, as long as they stay smooth. You want a deep rib, with plenty of shape to it, and a fairly level underline. You can feed a little flank into a really green one, but make sure there is some depth there to start with. Also, make sure they aren't tight in their heart girth - if one is tight in their fore flank and especially if they also break behind their shoulders, it's often a sign of a hard doer and can indicate structural issues as well.
Try to find one that doesn't have much excess brisket, or leather under his neck and in his navel/sheath. A little bit isn't the end of the world, but very much can be unless you're showing Americans. Longer necks are more attractive, but the main thing again is proportion - too short a neck really hurts a show calf's balance and look. Pretty heads help, too. Hair is good - you can always make it better with work, but if it's not there genetically no amount of work will make it very good. If the genetics are there you can do so much with hair - hairy ears are a good sign.
Also, maybe as important as anything, especially for a first timer, is attitude. A nervous or mean calf will take all the fun out of the project and may make you not want to do it again - an easy going one is so much more fun to work with. I used to have the attitude that we could handle most anything, but life's just too short for the misery a bad one will put you through, not to mention it's just not worth anyone getting hurt.
Finally, I only have one thing to say on the subject of cost - it costs just as money, and is just as much work to feed a common one as a good one. I'm definitely not saying spend more than you can afford, just remember that buying the cheapest calf isn't always cheapest in the end.
Good luck.
(DISCLAIMER - We are hog farmers, so we don't know a lot about cattle yet and our 4-H club doesn't have a beef leader so we get to do that too!)
