I assume you are still in college since this is the first time you SMS. 

Well, if she is a party animal you can ask her about the next happening and will she be attending?

If she is the hardcore homework girl ask her about homework which page and don't be too dumb.

If she is a normal girl next door just text her and ask her about some opinion about work, fashion or things which might be interesting for her.

Kindly avoid awkwardness at all cost as it will jeopardize your chances at this early stage.

My tips is just theoretical. Practical pandai pandai laaaaaaaaa.

Here's a pickup line for you. Use at your own risk by analyzing the situation. LOL

"Hey that day i saw one of your photo from XXX. How's that place? Been so long since the last time I went there. Ohh I see I see... So cool eh. But I can't view some other of your XXX photo because it seems you close your profile only for friends."

Note : Sure got photo of a vacation or trip... 

"You know that day I saw someone similar to you on FB. And i thought it was you. Seriously ah? I add you then send you the link take a look"

Note : Try get any significant faces you can find online regardless you kenal or not. Saje tunjuk tunjuk abit for humor sake.

Good. Means she remembered your face. You need to throw a trump card to get her name SMOOTHLY~

Pickup...

Cool line : "Oh hi! May I know your name? I totally forgot when you smiled at me.

Spontaneous line : "Hey, you know it's not fair you know my name and I don't know yours. Nvm, just sketch it and I shall guess it"

Gentlemen line : "Hello there. How's the english class going? And how may I address you as? Ms. ???"

Sorry not pro. Depends on situation and tone of conversation.