Editor's note: Inc.com columnist Alison Green answers questions about workplace and management issues--everything from how to deal with a micromanaging boss to how to talk to someone on your team about body odor.

A reader writes:

I'm having a problem with one of my staff members; let's call her Jane. Jane is a staff assistant and a hard worker who wants to stay in the office and move up the ladder.

Jane does good work, but some people in the office don't take her seriously. Part of this is that she's not assertive enough, which I've talked to her about. The other part is her appearance. This is an office where how you present yourself matters, and you need to cater to that to get ahead. Jane is the first person you see when you enter our office, and her clothes are overly casual and often don't fit quite right, she doesn't wear makeup, and her hair is kind of a mess. She's young, and I'm sure some of this is inexperience. I've hinted to her that it would help if she looked more professional, but it hasn't really changed anything.

I really like Jane and want her to move ahead. My concern with coming out and saying "You need better clothes, to wear makeup, and get a new haircut" is that Jane will get offended. Do you have any advice on how to address this?

How comfortable are you with candid, potentially awkward conversations?

Telling Jane to try to look more professional hasn't worked, so you're going to need to get more explicit about what that means.

Why not take Jane out for lunch or coffee and say something like this: "I think you have huge potential, and I want other people to see it too. In our line of work, projecting a polished, professional image matters. I think it's something you're still figuring out how to navigate, just like a lot of people early in their careers. I want to help."

You might even say, "Someone had this conversation with me when I was starting out and it was really helpful, so I'm going to have it with you." The vibe should be that there's nothing wrong with her for needing someone to help her with this.

Then, rather than saying that Jane looks messy, present it in terms of needing to come across as more polished. And here's the key: You need to explain what you mean by that, because it's quite possible that Jane has no idea. Saying something like, "In this office, it really helps to pick clothes that are more tailored, to make sure they're ironed and that your shoes aren't scuffed (or whatever you've noticed that would help), and to wear your hair pulled back" is more useful than just "you look unkempt." You might also point out people in the office who do dress professionally, and what they're doing that's working.

And keep in mind that Jane may not feel she's able to afford new clothes, especially if she's early in her career. You don't want to give her the (frustrating) impression that she needs to spend a boatload of cash to be perceived as professional, so consider suggesting some low-cost options. You can often find nice business suits in consignment shops, after all.

I'd leave makeup out of it, though, since there are plenty of professional-looking women who don't care for lipstick.

Ultimately, what's most important is to be specific about what you mean, and to do it in a way in which Jane can feel normal and not embarrassed.

Want to submit a question of your own? Send it to alison@askamanager.org.