I get compliments on my dressing from time to time. I suppose it makes me a little uncomfortable, simply because I don't like a lot of attention, but I genuinely appreciate the compliments and would rather get them than not. I say thank you and often add some other piece of information, such as where I got a particular item or what my motivation was for buying a particular item.
When I give compliments, I generally try to focus more on the outfit itself rather than the person, at least if it's a stranger. So instead of saying, "You look great!" I will say, "That's such a pretty top" or "I love the color of your jeans" or "Those shoes are amazing!" I think that helps the comment feel less creepy and less body oriented. If the person I'm admiring is a friend, I will probably start with "You look great!" and then say what I like about the outfit.
I'm in my forties, and I do sometimes dress down to avoid being noticed, especially if I'm going to be in the company of a lot of men. Sometimes I also avoid wearing makeup for that reason. I can certainly understand the need to dress very conservatively if you are female in a male-dominated field, especially when you are just starting out. I use clothing for lots of emotional reasons: to feel happy, to feel relaxed, and to feel safe. It all depends on your emotional need at the time.