One thing you can is find out what are the common interest that
the both of you share. Make use of the common interest shared to
your advantage.
For example , if both of you like classical music , get hold of
some concert tickets and ask her whether she would be interested to
go for the concert. Assume that it is the first outing , she will
definitely bring her friends. If you wanna get her friends out of
the picture , you better hope that they 100% don't like classical
music and then you ask them whether wanna join you 2 for the
concert. Surely that won't wanna go. This is to prevent her from
saying , "how come you never ask my friends along as well , only
ask me along?" Then she will not suspect anything....
Well it worked for me though but last minute she could not make so
I had to go for the concert all by myself 
