I'm working on my instrument rating and wondering if I can practice ILS approaches without an instructor? Using a safety pilot, also not instrument rated, could I call approach stating VFR would like ILS into X. Or do I just call the tower and ask for it there? Or can I only do this with an instructor?
Sure you can! There's nothing wrong with shooting practice approaches if you're not instrument rated (in the US, at least) as long as you don't actually accept an IFR clearance.
You would probably be better off asking approach control for practice approaches rather than tower, if you have approach available to you.
Yes, you can request practice approaches under VFR, however you or a safety pilot needs to take over airspace monitoring if you put on an IFR hood.
Unless your question is FAA specific, here are some excerpt from the German AIP.
And also the associated phraseology to request: