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.