Summarize this article in one sentence.
Open Snapchat and tap the ghost icon at the screen's top. In the resulting menu, select "Add Friends." After that, you'll be able to add her with her username, through your phone's contacts (though you'll need to already have her number), or with a special Snapchat code. If you don't have her username, number, or Snapchat code, you can always add her by finding her in the friends' list of a mutual friend. Avoid following her on multiple platforms, like Snapchat, Twitter, and Instagram, on the same day. Doing so might come across as too strong. Wait a few days before sending that first snap. Snapping her right away her might seem a little desperate. After that, snap her once every other day with things like your dog eating snow, street performers, and the pile of homework you got in math class. When you send her casual snaps regularly, she'll come to expect hearing from you. This will develop naturally into more snaps in the future. As you get to know her better through your casual snapping, you'll start exchanging snaps more frequently. Sending a bunch of snaps too soon could be a turn-off, though if she keeps responding, it's likely she wants the conversation to continue. If she responds to you, allow the conversation to develop as though you were chatting in person. Ask her questions about the things she says to show that you're listening. Use your snaps to paint her a picture of what you like, what you do, and what's important to you. Phrases like "hey, what's up," "what you doing," and "what's going on" won't catch her attention and may go unread. Weird and overly silly comments might also result in her ignoring your snaps. Instead of "hey, what's up," try snapping her a pic in a cowboy hat with the message, "howdy." Aim for a friendly, interested, playful tone. For example, you could write, "they'll never catch me" with a snap of police driving by.

Summary:
Add her on Snapchat. Send her casual snaps a few days after adding her. Increase the frequency of your snaps gradually. Tailor your responses to the situation for a natural conversation. Avoid worn-out and over-the-top expressions.