If the DOM code has ID's that's where I would start.
If you need to add something to your code to be able to access the elements, I would say to have some custom classes that can be identified with selenium (doesn't work with coypu though). This will only help if you manage to get a custom class that will work across your entire program and with the help of the developers (they usually forget to add this class because it is "for the sole purpose of automation so not worth the effort").
When everything else fails Xpath is your solution.
You can grab xpath expresions with a firefox extension called FirePath, you might also find xpath finder useful.
You can always use the inspector from the browser itself to find any of these (Id, Css, Xpath).