哪个是在除XPath之外的selenium webdriver中定位元素的最佳方法？

The application which I'm testing is fast developing, and new features keep being adding, requiring changes to the testing XPaths. So the selenium scripts which were successful before now failed as the XPaths have changed. Is there any reliable way to locate element (which will never change)? FYI, I thought of using ID's but my application does not have ID's for each and every element as it is not recommended to give ID's in the code.The application which I'm testing is fast devel