Back off for a bit. Timing is everything. Do not move in on the friend for at least a couple of months. Remember, women talk, and I'm sure that the girl you hit on told her friend that you did. If you move on to the friend, she will feel like she's your second choice, which she is. Your best bet, in order to ensure that you're "first in line" for the friend, is to simply stay in frequent social contact with her (but don't ask her out). During those social (but not romantic) encounters, she'll decide whether she's attracted to you or not, thereby making your job easier when enough time has elapsed between your hitting on the original girl and the time you make a move on her friend. In fact, you should be able to pick up on the signs that the friend is attracted to you during those social encounters. If you don't, then don't bother hitting on her, since you're likely to get shot down and blow your chances at perhaps having a couple of "pivots" for finding other women.
