Learning Contemporary Effects
When you are working on any new sound, such as singing and playing at the same time, it helps to listen to many examples of players performing the desired effect. Notice the octave the voice is in: it will be different depending on whether you are a female or male (most males will not be able to sing in the same octave as high flute playing for example). Isolate the effect on one note: if that works, link it to other notes. Build your phrase this way. I think it is wise to learn one special effect every few days to reinforce the work you just did. Most contemporary notation is quite approximate for the effect (isn't all musical notation somewhat approximate after all), so try to work more on the auditory result and rely less on the visual notation in front of you.
It is always interesting to notice the different qualities of vibrato possible on the flute. When you are working on tone studies, carefully observe the speed, amplitude, and quality of the vibrato you are using. As a piccolo player, our vibrato naturally has to be smaller since the overall tone tends to be more lean in general. If you play piccolo, try doing your piccolo vibrato studies first and then switching back to flute: many flutists use too wide a vibrato and this simple change of perspective might be just the trick!