Shop around, ask questions, and study the animals you want to buy. This is a must if you want to buy great foundation stock to start. It's always good to shop around and compare prices, just like you would if you were going to a few clothing or shoe stores in the mall. Some producers may charge a little more money because they can or because their stock is high quality (i.e., registered purebred stock). No cow is alike, no matter how many individual cows you look at. Don't get caught up on just looking at pictures on the internet, as most of the time the pictures you see on-line are not what you see when you're standing out in the pasture. But that's not to say that it's wrong to have a producer send you pictures to look at, or to view pictures of heifers and cows on a producer's website. It's actually good to have both to go off of.
Most of the time when you are out with the cow in her pasture you get to see how she acts around you (as a stranger to her), her general temperament, how she walks, her conformation, etc. Visiting a producer also gives you a chance to talk with him or her about how [s]he raises her animals, what health problems they've gone through, how they manage their pastures and their cattle, and to also see the other cattle that they raise in addition to the one (or more) of interest. You also get to see where they live, what kind of land they raise their cattle on, their facilities and other things that may concern you. And ask questions; chances are that the producers you are visiting couldn't care less whether you are full of questions or not. Even they'll most likely be asking you questions about you and what you want to do with the cattle of theirs you're offering to buy. It also wouldn't hurt if you asked if you could take pictures of their cattle so you can study them further back home.
When you're at a sale barn or auction mart, it's a bit different. The cattle are shunted through pretty quickly, giving you only a few seconds to study them before they are sold to a buyer and shunted out of the ring again. Chances are you will not be able to meet the producer that is selling the cattle--except if it's a dispersal sale--so you are pretty much on your own as to deciding what cattle you can buy. It may help to go in the corrals behind the ring to have a look at the animals yourself before the sale to see if there are any worth bidding on. Don't choose something just because it looks cute or pretty, be more pickier about disposition, looks of overall health, conformation and body condition. And follow your gut instinct. Don't be disappointed if you've lost a bid on some heifers or a 3-in-1 that you were looking to buy, nor if you haven't found any worthwhile animals to buy at the sale you went to. There's always a next time, always a next sale to attend to if you couldn't find what you were looking for in a previous one. If you are really inexperienced and don't know what or how to think in a cattle auction, get a friend who has more experience with cattle to come along with you to help you pick and decide which is best and which isn't.