When shopping for the right phone for your child, think about your biggest concerns. If you want to know where they are, you'll probably want something with a GPS tracker. If your child is active and careless (what child isn't?) then it's important to look for a durable design.
If you want to encourage them to keep their phone handy, then choosing something with fun features, like games and photo apps, is a good way to ensure they'll keep track of it. If communication is your main concern, an inexpensive "dumb phone" will work well to teach them responsible cell phone usage before they graduate to a smartphone.
As you ease your child into the world of communication technology, be sure to stay nosy. If their device has access to the internet, use parental controls and talk about what it means to be a respectful and responsible person online. Talk to them frequently about who they're communicating with, and take time to discuss cyberbullying. It's important to keep all lines of communication open—not just those accessed through a phone.