How can I get useful error messages in PHP?

Quite often I will try and run a PHP script and just get a blank screen back. No error message; just an empty screen. The cause might have been a simple syntax error (wrong bracket, missing semicolon), or a failed function call, or something else entirely. It is very difficult to figure out what went wrong. I end up commenting out code, entering "echo" statements everywhere, etc. trying to narrow down the problem. But there surely must be a better way, right? Is there a way to get PHP to produce a useful error message, like Java does?