My friend really seems to like this guy at her school. She constantly asks me for advice, but I'm honestly not sure what to say. He seems to have an interest in her (he stares at her, teases her in a nice way, says hello and goodbye almost always, comes up to her a lot), but what can she do to farther continue the relationship? In other words, what is the next step?

Being that you are her good friend, then ask her if she wants you to tell this boy that she likes him, and does he like her? That's what I did when I was in school. Of course that was before cell phones, email, electricity, reagular phones. Of course writing letters was an option, but I found the pony express took so darn long.

If u don't know what to say, tell her you don't know!! She has to understand

The best step is communication.That is people talking together.(not texting)
Say hi and have a conversation.Thats it.It starts from people connecting with people ;

Tell her to say hi back when he says it.

Maybe one day, when he says hi, she can even add a "how are you?" and start a conversation. Maybe the conversation will lead to "would you like to have lunch together?" and then even to "What are you doing Saturday night?"

You can't meet people if you won't talk to them. So she has to talk to him, take a chance, and see what happens next. :)