most of this is personal preference. try to emulate professional photographers at shows. notice where they are sitting when they take photos. when out in the pasture, feedlot, which i have taken a lot of and patience is required to get the stance, or with calf tied up or held, if you want people to evaluate your product, they need a frame of reference they are comfortable with. it is worth sifting through less photos.
some tips off the cuff
the lens distorts and emphasizes what is in the middle of the lens. it will make the middle longer, and the ends shorter.
usually sit betweent the middle of the animal and the rear leg.
the perspective should be up slightly. this makes the animal appear more like it is when you are walking around in person.
find the angle which will not let the shoulder point stick out. you want it smooth, allow some brisket to show
the animal should be going slightly up hill so they don't look like they will mature in 4 years
the legs near you should be wider than the ones behind.
i like the rear like straight up and down, others like it slightly further back, with the front one straight up and down,depending on how it makes the hip look. modify how you want the hip to look by doing this
it goes without saying their feet should square when viewed from behind.
animals can be rocked slightly, even in the pasture by moving sligtly to get the rear leg straight up and down
others will take the shot more from the front to accentuate the quarter, a different shot at the shoulder, brisket, the top line, lifelines photo comes to mind, i like how his top line lookds like it has some width by seeing the other side slightly and how it makes him look clean up front.
some will put feet in the grass to hide, guess what, the feet
develope some prop to get the animal to perk their ears forward, some noise if you are by yourself, a clicker, a clacker, a cracker. something, you want that interested slightly reaching rather than held up look. when they are held up, sometimes they can turn a little sideways, which tends to make them want to move, then,... there go the feet. you want them to look like they just heard something interesting in class and are paying attention.
early morning or late evening is best with the sun BEHIND you. they lighting is not saturated, and you won't need a flash as in the mid day to bring out the lower parts. plus the animal won't be interested in sleeping and chewing its cud. well, i guess they will be interesting in eating, but in the pasture, i like it because it helps them move their feet to a different posture. some people like to shade the top line, others light it up depending on if you want to hide or show or accentuate somewhere else
a lot about photos is hiding things as well, like the course shoulder, too straight a set in the hocks, sickle hocks etc.
background is important too. allow contrast and uninterruped background, not a fence or trailer that ends with a bright background on one side of the shot and a dark one on the other, this fiddles with the camera's light reading and it will overcompensate
the key is to get into a routine that will initially eliminate big mistakes and allow you to relax when taking pictures. it's almost like showing.
after that, it's the pro's work, who will hopefully comment on faults, and my bias.
that said, one of my favorite bull pictures is of PS Powerplay