This is a bit broad... there's plenty of advice I could offer. Could whoever asked this be a bit more specific?

If you mean really general advice: Don't do it thinking you'll make money. At all. In fact, be prepared to lose money, possibly for a long time. If you can, get funding for all expenses sorted out for at least a year's worth of issues ahead of time, and have a good plan to draw in funding for it. That plan should *not* involve large numbers of sales, because there are absolutely no guarantees that you'll make it, no matter how well-prepared you are. If you don't have outside funding lined up, be prepared to pay 100% of expenses out of pocket.

Do it because you love it. Do it so that you can hold a copy in your hand (or if an online zine, see the completed issue posted publically) and have your heart skip when you think "I made this!" Do it because sometimes, you get to be the first place to publish a new writer, and literally change their life forever.