Start where you are comfortable playing (say a B), and slur up one note chromatically (as Micron said, being sure to use the proper fingerings), focusing on getting a good sound. This should give you a better feel for where the different pitches lie, and once you have learned to produce those notes, you can start attacking right in the second octave. Make sure you are supporting well, and you should have no problem.
the last post is correct, remember that you have to find notes on flute, not just force them out, you can also practice slurring up in octaves, be very sure you are doing the correct fingerings
the last post is correct, remember that you have to find notes on flute, not just force them out, you can also practice slurring up in octaves, be very sure you are doing the correct fingerings