Where to place and how to choose a bird bath
Location, location, location
Birds are attracted to the water, no matter where it is, stuck in the middle of the lawn, under a tree, in a flower garden, or near bushes, some birds will visit. So from the birds' perspective, you can't go wrong. However, if your desire it to attract birds, they are more likely to come if the bath is also near a food source (e.g., berries, bugs), nesting material (e.g., twigs, cut dried grass), or a tree, and NOT near predatory animals like dogs or cats. Be aware that birds can drop seeds that might grow near the bath, not to mention "droppings" in general which can present a health issue if children or pets play near the bath.
Your bird bath can be on a pedestal, suspended from a tree, or placed directly on the ground.
TIP: As an experiment to see if birds will visit the desired area where you would like a bird bath, place a flower pot saucer or plastic trash can lid (not metal) on the ground. Ensure it does not wobble; push dirt or gravel underneath to keep it level. Add about one inch of water. Keep it filled to one inch and clean for a week or two. If birds visit, wahoo, you've found a great location. If not, relocate the saucer. This tip will also determine your desire to keep the bird bath filled and clean. On the other hand, if the bird bath is a focal point to your garden/yard more than a device to attract birds, then it doesn't matter where you locate it (from a bird attraction standpoint) or even if there's water in it.
Choosing the bird bath
You have selected where you want your bird bath so you know how much space you have. Now it's time to determine what type of bird bath. Pedestal bird baths are popular because they provide visual appeal to us humans, but as previously noted, birds can be totally satisfied with a puddle of water in the street. Choose what meets your needs, a focal point on a pedestal, suspended from a tree, or a basin on the ground.
Start your search at your local garden center (e.g., Lowes, Wal-Mart, Home Depot) or nursery. Some places call them bird fountains, though that might include an actual fountain for moving water. You will find that there are lots of materials from which to choose, with concrete the most popular. Shy away from the polymer bird baths. Their lightweight material makes them less expensive, but also makes them more susceptible to tipping. If your objective is to have a bird bath suitable for, well, the birds, then make sure the bottom of the bird bath is not slippery or shiny. People like shiny bird baths while birds tend to prefer darker surfaces (again, think about the puddle of water on the road). Some advice you may see on choosing a bird bath includes selecting one that is not too deep; however, manufacturers of bird baths are aware that the bath portion should be shallow, so that's not a real concern.
Keep it clean
Whether your bird bath is for a focal point or a functional bath for visiting birds, you will need to periodically clean it. Even that focal point will collect rain water and have subsequent visits from birds, not to mention leaves and other debris. At a minimum, rinse the bowl portion by lifting it off the pedestal, lean it against the pedestal, and hose it down.