Congrats bro, you got her number. Honestly, you should be proud of yourself for getting to this point. Odds are she is freaking her freak right now that you asked her for her number. She's excited too... unless you're a creepy stalker. Anyways, now that you have worked up the courage to talk to her you do not want to mess up. This is precious time you have to work with. You have to play by three very important rules.
1. Don't text her right after you get her number
Even though the chase annoys me sometimes, I know it is what makes it fun. Let's say you get her number at night. Do not text her until the next morning. You want her to be waiting for your text. You always want to leave her wanting a little more. If you wanted cookies and I kept feeding them to you in bulk you would get so sick of cookies. You would no longer DESIRE them. You want her to desire you as you desire her. If you give her everything all at once, what else is there to give? That relationship will last for about five minutes.
Wondering and waiting can keep your relationship hot. You don't ever want to give off needy or lonely vibes. It is more attractive if you are with friends or working/schooling during the day and don't have time to talk every second.
Girls like guys that have friends and have other tasks to do than sit on their phone. As your relationship blossoms, you can make more room in your life to incorporate her into.
Heads-up, rule 1 and rule 2 sit on a fine line, so you have to be careful.
2. Don't take too long to respond
This can be tricky because I just told you to wait to respond. This rule applies after you have been texting for a while. Base it on how well the conversations flow. Obviously, if you ask her "what's up" and then wait four hours to respond to whatever she says, the relationship will go nowhere. Use your judgment and play on how quick she responds. Honestly, we are all looking at each other's texts and purposely waiting to respond (which I already wrote about why I think that is annoying).
Back to the desire topic above, don't respond at the speed of light where you look needy, but don't leave her waiting all day.
3. Be yourself
Oooh, yeah, Annabelle, that's such a good one. OK, yes, I know — "be yourself" is so obnoxious, but it's true. Hear me out.
If you find out that your love interest is a die-hard Cubs fan and you hate baseball, do not act like you like baseball. It is totally fine (and normal) to have different interests. If a subject comes up like religion or politics where you have a difference you should definitely talk about it, but liking baseball is not a red flag. You can appreciate what the other person has to say about Cubs baseball, but don't Google facts and try to keep the conversation going in that way. If you keep this act up, what happens when she takes you to a Cubs game and hints that wants you to propose on the field? That wouldn't be as special to you.
Obviously, this isn't the best example, but apply it to other more relevant things. You want her to love you for you — including your dislikes.